The utility model provides a throttling device of a lubricating oil circuit on a cylinder cover of an engine, which belongs to the technical field of an automobile engine and solves problems that the existing lubricating oil circuit on the cylinder cover of the engine can easily enable variable valve timing (VVT) to be corresponding too slow when the engine is at a low speed so that inlet pressure of a VVT oil channel is reduced, and an air inlet VVT can not work. The throttling device of the lubricating oil circuit on the cylinder cover of the engine comprises a cylinder body and the cylinder cover fixedly provided with a cylinder cover shield. The cylinder cover is fixedly arranged on the cylinder body, a main oil channel communicated with a cylinder body oil circuit is arranged in the cylinder cover, a first branch oil channel communicated with the main oil channel and used for lubricating a camshaft of the engine is arranged in the cylinder cover and the cylinder cover shield, and a throttling structure for controlling flow and pressure in the first branch oil channel is arranged on the first branch oil channel. The structure of the throttling device is convenient to process, and a throttling hole diameter communicating with a lubricating oil channel of the camshaft can be adjusted by changing a throttling block. Lubricating oil on the main oil channel in the cylinder cover can be distributed reasonably for working usage of the VVT and for working usage of lubrication of a shaft neck of the camshaft and a hydraulic tappet.