The calculation model of lubrication system and the dynamic model of bearing for 1.8VVT engine were established and the parameters such as main oil channel pressure, lubricant flow at bearing place, axis track of bearing and minimum oil film thickness were calculated and analyzed. Then the minimum lubricating pressure of lubrication system under different engine speeds was acquired by analyzing the lubricating oil pressure demand of the key parts such as bearing, CAM and VVT system and the calculation results could provide theoretical basis and boundary conditions for the design of lubrication system. The simulation results show that the inlet pressure of engine lubrication system has little effect on the minimum oil film thickness of bearing lubrication. The measured value of hydraulic power in charge of supplying the lubricant for the original system exceeds the theoretical demand value by up to 72% and so the original lubrication system has the problem of excessive oil supply at high speed.