Abstract: CoCrFeNiCuAl_0.8 high entropy alloy was prepared by selective laser melting(SLM).The forming quality and density of the alloy at different laser heat inputs (0.06-0.36 J·mm^-1) were studied, and the optimal forming process parameters were determined. The microstructure and tensile properties of the alloy under the optimal forming process parameters were analyzed. The results show that the density of SLM formed alloy increased first with the increase of heat input, and basically remained unchanged when the heat input was larger than 0.15 J·mm^-1. When the heat input was 0.34 J·mm^-1, the alloy had the maximum density of 7.5 g·cm^-3, and the optimal process parameters were as follows: laser power of 270 W and scanning speed of 800 mm·s^-1. The SLM formed alloy had a dual-phase structure consisted of disordered body-centered cubic phase (A2 phase) and ordered body-centered cubic phase (B2 phase), and the microstructure was composed of columnar and equiaxed grains. The yield strength, tensile strength, percentage elongation after fracture and percentage reduction of area of the alloy were 651 MPa, 840 MPa, 22% and 23%, respectively.The fracture mechanism was ductile fracture.