Preferential tax is one of the important means for supporting SMEs.In this paper，the effect of tax preferential policies for SMEs is analyzed.Through observing the tax burden of micro enterprises，analyzing the influencing factors of the sense of tax burden，and simulating various preferential policies，the paper concludes that：there is still a considerable policy space for further tax cuts，preferential policies need to be implemented；the sense of tax burden is affected by many factors.According to these results，we put forward the corresponding policy recommendations.