The invention discloses a high shearing force preparation of microcrystalline lactin, including steps of: (1) mixing solid lactin and water with a certain proportion, stiring and heating until the latin is fully dissolved; (2) cooling the latin solution to a predetermined temperature to obain hypersaturate solution of latin; (3) turn on a shear in a crystallizer, to stimulate crystallization of the solution by high shear force; (4) fast separating latin crystal from mother liquid by continuous centrifuge; (5) drying obtained latin crystal; (6) product of microcrystalline lactin is obtained byscreening. The invention not only stimulate crystallization of mother liquid by shearing force, in order to realize control of the crystal forming process, and obtain product with centralized grain-size distribution, but also avoids mechanical crushing in the preparation, so that crystal structure is protected, and generation of non-crystal granular is also avoided. Further, the invention combines centrifugal and vibrating drying, thus crystal exhibit excellent fluidity and dispersity, and crystallization time is short.