NOVELTY - The three-dimensional system comprises a regulation pool (1), a light reaction block (2), a water storage tank (3), an anaerobic reaction tank (4), a sewage input pipe (5) arranged in the regulation pool, and a water recycling pipe arranged at a bottom of the water storage tank. The regulation pool is connected with an upper input of the light reaction block. The water storage tank is connected with a bottom output of the light reaction block. The anaerobic reaction tank is arranged below and connected with the regulation pool.    USE - The three-dimensional system is useful for sewage purification.    ADVANTAGE - The three-dimensional system is capable of economically and safely purifying the sewage with reduced energy consumption in an environmentally friendly manner.    DETAILED DESCRIPTION - The three-dimensional system comprises a regulation pool (1), a light reaction block (2), a water storage tank (3), an anaerobic reaction tank (4), a sewage input pipe (5) arranged in the regulation pool, and a water recycling pipe arranged at a bottom of the water storage tank. The regulation pool is connected with an upper input of the light reaction block. The water storage tank is connected with a bottom output of the light reaction block. The anaerobic reaction tank is arranged below and connected with the regulation pool. A biogas collection pipe is arranged on an upper anaerobic reaction tank. A sludge output is arranged on a bottom of the anaerobic reaction tank. The light reaction block includes a uniform water collector, a light reaction pipe and an outflow collector, and is arranged in a transparent box. The uniform water collector is placed on the upper light reaction block. The outflow collector is placed on the bottom of the light reaction block. The light reaction pipe is uniformly distributed between the uniform water collector and the outflow collector, and is transparent pipe. Ends of the light reaction pipe are connected with the uniform water collector and the outflow collector respectively. A pressure control valve is arranged on the bottom of the light reaction pipe. The upper input of the light reaction block is placed on the uniform water collector. The bottom output of the light reaction block is arranged on the outflow collector. An intersecting surface has semicircle shape. A photocatalyst to purify the sewage is coated on the semicircle surface of a light reaction pipe inwall. A coat thickness of the photocatalyst is 2-4 mu m. An inclined baffle is arranged on one side of the regulation pool. An angle between the baffle and the horizontal plane is 40-60 degrees . The baffle is fixed jointed to the regulation pool inwall. A bottom of the baffle and the bottom of the regulation pool has 4-10 cm interval. A water mouth is: arranged on an upper part of the baffle; and a groove or several round holes. A height of the water mouth to the regulation pool is 1/2 to 3/5 of the regulation pool height. The sewage input pipe inserts into bottom of the other side of the regulation pool. A drain outlet is arranged on the bottom of the other side of the regulation pool, and has L shape structure formed by a vertical pipe mouth and a horizontal pipe mouth. The drain outlet inserts into the upper part of the anaerobic reaction tank. A bottom surface of the regulation pool is smooth. Bottom sides of the regulation pool inclines to the drain outlet and forms a slope. Bottom grades of the regulation pool are 15-30 degrees . A joint of the vertical pipe mouth and the horizontal pipe mouth is in arc transition. An upper end of the vertical pipe mouth is in funnel shape. A first water level sensor and a second water level sensor are arranged on a side wall of the anaerobic reaction tank between the biogas collection pipe and the horizontal pipe mouth. The first water level sensor is flush with an upper surface of the horizontal pipe mouth. The second water level sensor is placed above the first water level sensor and placed below the inlet of the biogas collection pipe. A gas control valve is arranged on the biogas collection pipe. The first water level sensor, the second water level sensor and the gas control valve are connected to the controller. A top part of one side of the regulation pool includes a safety pipe and a water outlet. The safety pipe and the water outlet are parallel arranged. A liquid control valve is arranged between the entrance of the safety pipe and the water outlet and connected to the controller, and seals off the entrance of the safety pipe and the liquid of the water outlet. The regulation pool and the light reaction block are integral, and has fission structure. The water outlet of the regulation pool is connected with an upper water inlet of the light reaction block via a drainage pipe. An irrigation valve is arranged on the drainage pipe and connected to the controller. A third water level sensor: is arranged on the baffle; flush with the water outlet of the regulation pool; and is connected to the controller. Thermal expansion bags are arranged in the regulation pool and connected to the controller. A pipeline mixer is arranged on the sewage input pipe. A flocculant input pipe is connected to the sewage input pipe behind the pipeline mixer. The transparent box is arranged outside the light reaction block. A light intensity sensor is arranged on the box and connected to the controller.    DESCRIPTION OF DRAWING(S) - The figure shows a flowchart of a three-dimensional system for sewage purification.    Regulation pool (1)    Light reaction block (2)    Water storage tank (3)    Anaerobic reaction tank (4)    Sewage input pipe. (5)