With the rapid development of the micro/nano-electro-mechanical systems(MEMS/NEMS)in recent years,it is quite necessary to have a deep insight into micro and nano-scale fluidics.As the size of the fluid system decreases to micro or nano scales in the MEMS/NEMS,boundary slip effect must be taken into account.In the past few decades,some studies have been carried out on the micro-scale and nano-scale flow,and more and more details of the flow have been observed and revealed.However,in many cases,part or whole of the MEMS/NEMS itself vibrates due to certain reasons.Neither the velocity slip phenomenon nor how the oscillation frequencies,oscillation amplitudes and Knudsen numbers influent the flow in such kind of oscillation system is thoroughly investigated.In this paper,the numerical study on flow with an oscillatory boundary by LBM is carried out,which could overcome certain limitations of the conventional numerical approaches and reveal the effects of oscillatory boundary flow on boundary slip.The two-dimensional pressure-driven gas flow in a microchannel with an oscillatory boundary is simulated using Lattice Boltzmann method.The distribution of mainstream velocity and slip velocity on boundaries in different oscillation frequencies,oscillation amplitudes and Knudsen numbers are obtained and analyzed in detail.The results show that velocity slip is obviously observed in gaseous flow on the upper and lower plate.The slip velocity increases along with the flow direction and enhances remarkably near the outlet while the flow in the region far away from the oscillatory boundary keeps steady.Due to the influence of oscillatory boundary,the magnitude of the slip velocity on upper plate oscillates periodically,and the average slip velocity on the upper plate is greater than that of the lower one.As the oscillating frequency,amplitude and Kn number increases,the slip velocity on upper plate increases substantially.The slip velocity on lower plate changes with Kn number linearly,and the overall velocity of the gas in the microchannel increases with Kn number.