Dolomite, as an important type of sedimentary rock, has attracted significant research attention due to its significance in either science or industry. Despite research over than 200 years, the origin of dolomite still remains one of the most debated subject in sedimentary geology, as commonly termed as Dolomite Problem. Recent culture experiments have demonstrated that microbial mediation helps to overcome the kinetic barriers limiting the formation of dolomite; dolomite can precipitate from aqueous solutions under Earth surface conditions. However, the occurrences of primary dolomite in ancient rocks, especially in paleozoic rock records, have rarely been reported. In this study, we reported the observations of primary dolomite in the Middle Cambrian evaporate sequences (Awatage Formation) from Well Hetian 1 in Tarim Basin, NW China. The results will improve our knowledge on the origin of dolomite in geological past.