The invention provides a tree-shaped baffle gas-driven engine oil-gas separation device. The tree-shaped plate gas-driven engine oil-gas separation device comprises a pre-separation device and an initial separation device, the pre-separation device and the initial separation device are arranged in an installation groove in a cylinder cover, an air inlet is formed in the installation groove, the initial separation device is composed of at least two tree-shaped baffles, the tree-shaped baffles are arranged in the installation groove in parallel, an exhaust hole is further formed in the cylindercover, a gas outlet pipe connected with a gas-driven oil-gas separator is arranged on the exhaust hole. The tree-shaped plate gas-driven engine oil-gas separation device can perform secondary acceleration on an oil-gas mixture, large oil drops and small oil drops are separated respectively and flows out through an oil return cavity, the separation efficiency is high; on the adsorption of the smalloil drops, a filter element cannot be blocked by residues due to secondary accelerated impact force, so that the filter element does not need to be replaced periodically, the problem of regular replacement and maintenance can be solved.