Abstract: To solve the problem of common injection allocation method in which remaining oil distribution is not taken into account,a new injection allocation method for sub-layer was studied.The quantitative relationship between recovery percentage of recoverable reserves and cumulative injection volume multiple was deduced based on Lifecycle Theory and Logistic Growth Law.According to the distribution of remaining recoverable oil in various su-blayers,a new method of injection allocation for separate injection well based on remaining oil distribution was put forward to improve sweep efficiency and producing degree.Refined numerical simulation was used to study the adaptability of thickness method,formation capacity method and separate injection allocation method to the oilfield development stage.The result showed that thickness method is recommendable when water cut is less than 50%,remaining oil method is prefered when water cut is within the range of 50%-80%.Pilot test was conducted on Well F6 of SZ Oilfield with remaining oil method and showed that water cut decreased by 8% and net oil production increased by 7 766 m3.This indicated that the adaptability research result of the new separate injection and injection allocation determination method can be used to guide the optimized adjustment of the separate water injection.