The invention relates to a petrol engine with turbo charging, which comprises a cylinder body, a cylinder sleeve, an intake valve, a spark plug hole, an exhaust valve, a combustion chamber, a crankshaft, a connecting rod, a piston, an intake manifold, an exhaust manifold and a turbo charging device. The petrol engine also comprises a twin cam shaft valve timing adjusting structure arranged above a cylinder head; the twin cam shaft valve timing adjusting structure ensures that an admission cam shaft and an exhaust cam shaft is in transmission connection with the crankshaft through a timing chain; and the twin cam shaft valve timing adjusting structure is used for continuously and changeably adjusting the opening times of the intake valve and the exhaust valve of the combustion chamber, therefore, the fuel utilization and the rotation speed and the output power of the engine can be improved. The turbo charging device can increase the intake pressure of the engine, and quicken the combustion of the fuel of the engine, so as to enable the combustion to be more sufficient, therefore, the output power of the engine is improved, and the exhaust emissions are reduced. A three-way catalysis device is arranged on the exhaust manifold, therefore, the harmful gas emissions can be reduced.