NOVELTY - The system has an oxyhydrogen generating unit (5) comprising an electrolytic bath filled with an electrolyte, and a set of electrodes placed in the bath and electrically connected to a solar power generator (31), where the electrode utilizes the electrical energy output by the solar power generator to electrolyze the electrolyte to generate an oxyhydrogen mixture. A combustion unit (6) placed in housing (2) comprises a blower (61), which utilizes the mixture as fuel to generate heat, where the blower heats air in an airflow space (22) to generate airflow to drive fans (42) to rotate.    USE - Compound power generating system for generating wind energy, hydroelectric energy, solar energy and thermal energy.    ADVANTAGE - The system utilizes different numbers or sizes of fans and increases the number of intakes to increase the flux of an updraft in the airflow space to increase the power generated by a kinetic generator, thus improving the power generating efficiency. The system generates updraft air by burning the oxyhydrogen mixture, and has a simple structure. The system utilizes the solar power generator, the oxyhydrogen generating unit and the combustion unit to generate the updraft air to drive the kinetic generator, without the need for water to generate power, thus ensuring that the system is environment-friendly. The system has a housing unit comprising a cover placed on an upper edge of the housing and used for covering the vent, such that the external debris and rain can be blocked to protect the parts in the housing in an effective manner. The system comprises a draw unit for bringing external air into the airflow space, and the draw unit has four bases correspondingly connected to the four intakes and respectively placed on each inclined face, and four draw fans are respectively placed on each base for bringing external air into the airflow space, so that the draw fans increase the amount of introduced external air, and the increased flux of the updraft air increases the rotational speeds of the fans, which boosts the amount of generated power. The collected solar energy is transformed into electric energy to drive the oxyhydrogen generating unit to generate fuel gas, and the fuel gas is burnt by the combustion unit to generate the updraft air to cause the fans to drive the kinetic generator to generate electrical energy, so that the solar energy is indirectly transformed into the mechanical kinetic energy to drive the kinetic generator.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a compound power generating system.    Housing (2)    Power unit (3)    Rotation unit (4)    Oxyhydrogen generating unit (5)    Combustion unit (6)    Hollow housing (21)    Airflow space (22)    Vent (23)    Intakes (24)    Solar power generator (31)    Kinetic generator (32)    Rechargeable battery (33)    Shaft (41)    Fans (42)    Blower (61)    Inclined faces (211)