Based on the observations of 9 outcrop sections, 320 well cores and 980 thinsections from Tarim Basin and combined with analysis of the shapes and features of image logging facies, seismic facies and seismic profiles, the Ordovician sedimentary thickness are reconstructed and five phases of Ordovician lithofacies palaeogeography maps of the basin are compiled. They are the maps of the Penglaiba(O1), the early and late Yingshan(O1-2), Yijianfang(O2) and Lianglitage (O3) ages. During Penglaiba to Yingshan ages, the sedimentation behaved difference in the east from in the west of the basin, and during Yijianfang to Lianglitage ages, the sedimention turn to be difference in the south from in the north of the basin because the tectonic stress of the Tarim plate margin transformed from extension to compression. Platform margin and inset reefs widely developed during every age. It is suggested that the Ordovician platform margin and inset reefs are an important domain for exploration and recent reserves increase in Tarim basin.