Perform fluid simulation on the helical intake port - valve - cylinder flow field under the condition of steady flow testing rig . the results under different valve lifts are gained . the research of this paper is practically useful 对所建立的模型进行了稳流实验台条件下气道-气门-气缸内的三维定常流动模拟计算,计算了不同气门升程下气道的性能评价参数。