Abstract: Slotted pipe completion is the main well completion method for horizon wells both in China and abroad.Water plugging plays an important role improve the whole development effect of such horizontal wells.This paper analyzes the current situation of the water plugging technology of slotted pipe horizontal wells,summarizes and discusses the difficulties and the developing trend.It presents that the annular separation locating injection method is the subjective technology studied and applied abroad.Furthermore,to improve the performance of annular separation materials is the key to apply this method effectively.