NOVELTY - Natural method for treating urban household wastewater comprises introducing wastewater into precipitating well, precipitating solid pollutant in the wastewater into mud, and making supernatant into wastewater supplying pipe; adding beneficial microorganism into the wastewater supply pipe and mixing with the supernatant; and flowing the mixed solution, in order, through chief blind ditch, leaking blind ditch, sand draining bed and into soil around the sand draining bed. The beneficial microorganism is attached on the sand draining bed and soil granules around.    USE - A natural method for treating urban household wastewater.    ADVANTAGE - Wastewater is introduced into soil, thus microorganism gains best living environment and grows fast to degrade organic pollutants in the wastewater. Plants in soil absorb minerals from wastewater. The root bark of the plants absorb and store heavy metal in the wastewater. The method has wide use, adaptability to various scales, flexibility and brilliant prospect.    DETAILED DESCRIPTION - Natural method for treating urban household wastewater comprises:    (A) choosing a land and installing a set of wastewater treating system on it; where the system comprises a chief blind ditch for inputting wastewater; multiple parallel leaking blind ditches vertical to the chief blind ditch; one end of every leaking blind ditch is connected with the chief blind ditch, and the other end is closed; a sand drainage bed positioned below every leaking blind ditch; a leaking gap formed at the bottom of the leaking blind ditch and connected with the sand drainage bed; a water collecting ditch, which is a visible ditch, located at the outer side of the leaking blind ditch and vertical to it; a leaking gap formed on the wall of the water collecting ditch, corresponding to one side of the leaking blind ditch; a sand separating zone between the water collecting ditch and the leaking ditch; wastewater connecting pipe inserted into the ground and connected with the chief blind ditch; beneficial microorganism inlet opened on the wastewater connecting pipe; a wastewater precipitating well installed on the upstream of a wastewater supply pipe; overflow port of the wastewater precipitating well connected with the inlet of the wastewater supplying pipe; and dense plants arranged on the ground of the wastewater leaking system; and    (B) introducing wastewater into the precipitating well, precipitating solid pollutant in the wastewater into mud, and making supernatant into the wastewater supplying pipe by the overflow port of the precipitating well; adding beneficial microorganism into the wastewater supply pipe and mixing with the supernatant; making the mixed solution flow in order through the chief blind ditch, the leaking blind ditch, the sand draining bed from the leaking gap of the leaking blind ditch and into soil around the sand draining bed; at that time, the beneficial microorganism is attached on the sand draining bed and soil granules around; organic matters in wastewater are absorbed on the surface of granules are used as nutriments to grow fast so as to form biological film; root of the plants absorb mineral nutriments from the wastewater and grow well; root bark of the plant absorbs heavy metal from wastewater and stores the heavy metal in the cell gap of the root bark; and various pollutants are removed from the wastewater and clean water is gained; and making clean water in treated soil by the sand separating zone, permeate into the water collecting ditch by leaking gap on the lateral wall of the water collecting ditch and draining the clean water out from the drainage port of the water collecting ditch.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram illustrating the natural method for treating urban household wastewater.