Abstract: Microscale gas flow was simulated using latticeBoltzmann method(LBM)with bouncebackandspecular reflection(BSR)combination scheme. Good agreement was achieved between the simulation results and the published research data. The relationship between the selection of proportion coefficient of BSR and Knudsen number was analyzed. The results showed that when Kn∈(002，016)， the proportion coefficient initially reduces， then increases， and a minimum is achieved in 0055~0072. Based on the results， the proportion coefficient is modified， and simulation results are significantly improved， which provides a reference for LBM simulation of microscale gas flow.

Key words: latticeBoltzmann method(LBM), microscale flow, Knudsen number, slipvelocity, nonlinear pressure distribution