Preparation method used in manufacturing of efficient polycrystalline silicon wafer

The invention relates to a preparation method used in the manufacturing of an efficient polycrystalline silicon wafer. The preparation method comprises the following steps of: utilizing a conventional DSS polycrystalline silicon casting method for producing a silicon ingot, and preparing a polycrystalline silicon cast ingot in a polycrystalline furnace; cutting the cast polycrystalline silicon ingot into a plurality of cuboids; detecting minority carrier lifetime, impurities, shadow and the like of the cut polycrystalline silicon ingot, and removing a low minority carrier lifetime area; intercepting the silicon ingot along a crystal growth direction of the cast ingot by utilizing a machining method; cutting the intercepted silicon ingot according to a cutting line parallel to the crystal growth direction of the cast ingot, bar sticking and slicing; and finally manufacturing a cell slice with a cut silicon wafer by utilizing a conventional polycrystalline cell slice process. The preparation method not only can increase the grain size of the polycrystalline silicon wafer, but also can reduce the defect density of the polycrystalline silicon wafer, improve the quality of the polycrystalline silicon wafer, and increase the efficiency of the polycrystalline silicon cell slice.