Abstract: A series of Paleozoic strata(O₁-C₁) is widely distributed in the northwest of Heilongjiang Province. Combining the regional geological survey and scientific research results in recent years, the Ordovician-Carboniferous strata can be divided into three groups (Yilehulishan, Heihe and Liaoyuan Groups) with fifteen formations. The rock structures, fossil assemblages, sedimentary environments of each formation are discussed together with the open, evolution and extinction history of the Paleo-Asian Ocean. The integrated study on the Paleozoic strata provides such comprehensive data as lithostratigraphy, biostratigraphy and sedimentary environment for the evolution of the Ocean. According to the above stratigraphic records, it is thought that the Paleo-Asian Ocean was opened in the early stage of Early Ordovician, developed in the late Early Ordovician-Late Ordovician, converged in Early Silurian-Late Silurian-Middle Devonian and closed in Late Devonian-Early Carboniferous.