Abstract: In order to study a sedimentary environment of Taiyuan Formation and Shanxi Formation in Yangquan Mining Area,provenanceand source region structure b ackground,an analysis was conducted on the trace element and rare earth element of the mudstone in the are-a. The results showed that the lithophile elements in the are a were quite enrichment,the Ti,Zr,Hf and Th abundances of the high fieldstrength elements were higher than the upper crust and the Rb, Sr,Nb,Ta and other element were lo ss in some case. The rare earth elementtotal was high,the ratio of light and heavy rare earth elements and(La/ Yb)Nratio showed that the difference of the light and heavy「 areearth was obvious and that the light rare earth was enrichment and heavy rare earth was loss relatively. Eu was obvious negative anomalyand Ce was in a weak negativ e anomaly distribution mode. The analysis on Sr/ Cu,V/(V + Ni),Sr/ Ba,δCe,Ceanomand other feature pa-rameters showed that the mudstone in the study area was a trans ition phase-continental facies sedimentation and in a reduction,anaerobicand brackish water sedimentary environment. Based on the combination of the mudstone trace ele ments and rare earth element and the dis-criminant ilustrations,the source rocks in the study area were felsic rocks mainly. In comparison with Taiyuan Formation,the prov enance ofShanxi Formation was obviously affected by the granite. The structure background of the provenance area could possibly be the island arc ofthe mainland and th e edge of the active mainland.