Abstract: The new closed mechanical water location and shutofftechnology combines water location process with shutoffprocess by using a special packer and downholecommutator unit and performs multistage layer waterlocation and shutoff and producing horizon adjustmentwithout pulling out tubing strings. Leakproofness of thepacker and lubing strings can be verified step by stepwhen the packer is used in multistage. This paperintroduces the structure, mechanism and key parameters ofthis technology and the field test and application effects.