In order to solve the problem of low production efficiency in making heat sink use the commercial selected laser melting (SLM) equipment while keeping good thermal properties and mechanical properties , SLM technology is used to build Ni samples with different (20/40/60 μm ) powder layer thicknesses. The relative density, microstructure, thermal conductivity, thermal expansion coefficient and tensile properties of the samples are presented. Beyond the layer thickness threshold of the laser melting, the melting track is spheroidizing line. Within the layer thickness range can be melted, the samples can be nearly full densification. With increasing layer thickness from 20 μm to 40 μm，the primary dendrite spacing increases from about 347 nm to 635 nm. Thermal conductivity decreasing from 99.28 W/K ·m at 20 μm to 92.48 W/K ·m at 40 μm. Increasing from 25 ℃ to 100℃ ，the thermal expansion coefficient from 11.02×10^-6 m/(m·℃) to 12.9×10^-6 m/(m·℃) at 40 μm layer thickness, lower than 11.42× 10^-6 m/(m·℃) to 13.4×10^-6 m/(m·℃) at 20 μm. Tensile strengths of SLMed Ni samples are much higher than those of wrought Ni regardless of layer thickness and building direction. The production efficiency of using SLM technology form heat sink at 40 μm increases 34.6% compared with 20 μm.