The utility model discloses a small inverter double-cylinder generator set capable of efficiently reducing noise. Wherein a cylinder head of the engine adopts an overhead cam mechanism, and the generator is coaxially connected to one side of the engine. The overhead cam mechanism comprises a cam and a cam shaft for fixing the cam; wherein the synchronous belt transmission mechanism is connected with a crankshaft of the engine and the overhead cam mechanism, and the air guide transmission cavity is used for containing the synchronous belt transmission mechanism. The synchronous belt transmission mechanism comprises a cam shaft belt wheel fixed to a cam shaft, a crankshaft belt wheel fixed to a crankshaft and a belt connected with the belt wheels, a suction type impeller is arranged in the center of the cam shaft belt wheel, and an air inlet opposite to the cam shaft belt wheel and an air outlet opposite to the crankshaft belt wheel are formed in the shell wall of the air guide transmission cavity. According to the utility model, the cooling problem of the synchronous belt transmission mechanism is solved, so that the synchronous belt transmission mechanism can work reliably, and thenoise of the small-sized double-cylinder generator set is controlled and reduced more effectively.