The invention discloses a purification and enzyme digestion transformation method of a recombinant human insulin precursor and belongs to the field of preparation of recombinant human insulin and analogues thereof. In the invention, fermentation supernatant of a secretorily expressed recombinant human insulin precursor is purified by using a cation exchange chromatography column, two different washing solutions are used during washing of chromatography, the elution of target proteins is performed more quickly, the elution time is shortened, the precipitation of the target proteins is reduced and the volume of eluted samples is reduced; an eluting solution with pH 7.0 to 9.0 is used during elution, phase change operation does not need to be performed to eluted products, the eluted products are directly added into trypsin for enzyme digestion transformation and the transformation efficiency is high. The method disclosed by the invention is simple to operate, the primary purification and phase change operation of the fermentation supernatant are completed through one step of chromatography purification, the purity of the samples can be improved from 14 percent to 95 percent, the purified samples are directly subjected to enzyme digestion, the enzyme digestion transformation efficiency is above 95 percent, the production process is simplified and the cost is saved.