A dolomite unit near the Permian-Triassic boundary has long been used as the boundary marker in northwestern Sichuan but no biostratigraphically diagnostic fossils have been found in this units. Here we report the discovery of the conodont Hindeodus parvus and foraminifer disaster species from a microbiate bed in the dolomite unit above Permian coral beds at the Yudongzi section in Jiangyou of Sichuan Province. This discovery allows us to determinate the Permian-Triassic boundary in northwestern Sichuan and to understand the ecological and environmental changes across the boundary. We also present a detailed sedimentological analysis of the uppermost Changxing Formation and the lower-middle Feixianguan Formation