In order to improve building efficiency and ensure good accuracy and adequate mechanical properties of metal parts,a variable density rapid manufacturing process based on selective laser melting technology is proposed. Computer aided design (CAD) part model is divided into two building regions:shell region which is built by near-full-density producing method and internal region which is built by porous structure producing method. The transition condition of two producing methods are analyzed:transition between near-full-density structure and porous structure can be achieved through control of the melting depth of solid substrate by adjusting processing parameters. The experimental results of producing 316 L stainless steel parts by variable density rapid manufacturing process show that,compared to producing metal parts only using near-full-density producing method,producing efficiency is obviously increased,part weight can be reduced significantly and sufficient hardness can be obtained when using appropriate shell thickness. To larger dimension metal part made by this process,the experiments also show that the dimensional accuracy is greatly improved in addition to the above-mentioned advantages.