Abstract: The vertical components of 29 earthquake records received by 4 stations of Chengdu Network were analyzed with the single station stack spectral ratio method,and inverted the Lg coda Q0 for each path.Results indicate that the distribution characteristics of Q0 correlates with geotectonics closely.In tectonical active regions including Longmenshan fault,Xianshuihe fault,and Anninghe fault,especially in the junction of the three faults,Q0 exhibits very low values varying from 150-210.In most areas of Sichuan Basin,Q0 somewhat increases,with the decreasing of tectonics whose values being from 240-270.In the east part of Sichuan Basin,Q0 can arrive at 300.In the north part of Sichuan away from fault regions,Q0 varies from 250 to 300.