The invention relates to the field of a part forming process, and discloses a selective laser melting forming method of a multi-material part. The method comprises the following steps of S1, part model design, wherein during modeling, materials meeting forming needs are combined to be arranged according to the proper distribution rule, and part model design is finished in an optimized manner; S2,process model obtaining, wherein a designed part model is subjected to size and shape compensation, chamfering, remaining adding, process support design and the like, and a process model is obtained;S3, control file generation, wherein the obtained process model is subjected to layered slicing, the material kind, material distribution and material boundary information contained in each layer areextracted, and a control file guiding an additive manufacturing forming process is generated; S4, additive manufacturing forming; and S5, forming aftertreatment. According to the method, through the selective laser melting forming technology, the high-precision high-quality multi-material part can be formed.