The traditional manufacturing methods of metal matrix diamond composite tools usually have some typical disadvantages, such as lower holding strength of metal matrix to diamond grits, shorter protrusion height of diamond grits, and it is hardly to produce some specially designed diamond tools with complex structures. While 3D printing technology could provide a new development opportunity for the design and manufacture of metal-based diamond composites and diamond tools. By theoretical analyses, optimizations from metal materials, selective laser melting (SLM) forming process and diamond parameters were conducted. Based on this, the feasibility test and focused test about metal based diamond composites and diamond tools made with SLM were carried out. The results indicated that the use of SLM forming technology can improve the performance of metal-based diamond composites. However, there are still some deficiencies in the application of the new technology, which should be overcome in further researches.