The S136 mould steels with different particle sizes are fabricated by the selective laser melting (SLM) technique and the effects of particle size on phase compositions, microstructures, wear and corrosion resistance performances are studied. The results show that the forming parts with an average particle size of 22.8 μm have nearly no micro-pores, and their friction coefficient and wear rate are relatively small, but the corrosion resistance performance is the best and the corrosion weight-loss is 31.51×10-4 g·mm-2. If the average particle size is too small, there occur more cracks in the forming parts, however there occur more micro-pores when the average particle size is too large.