The invention discloses a four-stroke gasoline engine conducting burning and lubricating through two-stroke gasoline engine fuel and belongs to the field of four-stroke gasoline engines. A crankcase Bcomprises a cylinder body. A crankshaft is installed in the cylinder body. A crankshaft connecting rod is installed on the crankshaft. A left crankcase and a right crankcase are installed on the twosides of the crankshaft connecting rod correspondingly. A piston is installed at the tail end of the crankshaft connecting rod. A check valve is installed on the joint of the crankcase B and an air valve chamber A. A camshaft, a driving rocker and an air valve combination are installed in a cylinder cover in the air valve chamber A. The driving rocker is located on the camshaft and is connected with the air valve combination. Through the four-stroke gasoline engine, the problems of incomplete scavenging, insufficient burning and poor emission of a two-stroke gasoline engine can be solved, theproblems of the large size and large weight due to the effect that a traditional four-stroke gasoline engine is provided with an oil storage tank can also be solved, and the advantages of small size and weight, simple and convenient operation and maintenance, sufficient burning, high emission environmental protection property and low noise are also achieved.