Abstract：Based on the field outcrop observation of Shanxi formation in Xishan area,Taiyuan,by using the methods of sample analysis,thin-section observation,particle size analysis and so on,sedimentary microfacies and sedimentary evolution were studied. The results show that sedimentary environment of Shanxi formation of Permian is fluvial dominates delta deposition in Xishan area,Taiyuan. The sedimentary facies can be further divided into two subfacies and seven microfacies. Accompanying with the sea regression occurred from northwest to southeast during the sedimentary period of Shanxi formation in the research area,sedimentary environment is from delta front to delta plain sedimentary. The evolutions laws of sedimentary microfacies are via branch debouch bar microfacies→underwater distributary channel microfacies→underwater natural levee microfacies→distributary bay microfacies→marsh microfacies→branch channel→onshore natural levee microfacies→marsh microfacie.

Keyword：Shanxi formation;delta;sedimentary microfacies;particle size analysis;