The utility model discloses a 4-inch half-casing separate-layer fracturing pipe column. The packer comprises a constant-pressure sliding sleeve, a packing assembly, a hydraulic anchor, a releasing packer and a connecting pipe. The number of the packing assemblies is multiple. The connecting pipes comprise a first connecting pipe, a second connecting pipe and a third connecting pipe; a plurality ofsecond connecting pipes are arranged; the upper end of the constant-pressure sliding sleeve is connected with a packing assembly through a first connecting pipe; the plurality of packing assemblies are sequentially connected from bottom to top through a plurality of second connecting pipes; the uppermost packing assembly is connected with the hydraulic anchor through a third connecting pipe, theupper end of the hydraulic anchor is connected with the releasing packer, the constant-pressure sliding sleeve, the packing assemblies, the hydraulic anchor and the releasing packer are all provided with inner through holes, and the diameters of the inner through holes of the packing assemblies, the hydraulic anchor and the releasing packer are all larger than the diameters of the inner through holes of the constant-pressure sliding sleeve.