Through geologic studies of petroleum accumulation in the Tahe Oil Field, several problems referring to source rock, heavy crude accumulation as well as migration and accumulation network were discussed. Key events of petroleum accumulation in the Tahe Oil Field were charted in order. The oilfield has multiple source rocks, 3 sets of regional transportation formation as well as 4 sets of vertical migrating and adjusting "highway". Systematic studies of the oilfield may illustrate the multiple stages of accumulation and adjustment, and the compound distribution of reservoir.