The surface microstructures of 6061 Al-Mg-Si alloy coated with laser surface alloyed (LSA) Ni-Cr-B-Si powder and their sliding wear performance have been investigated. Experimental results show that there are three regions, as grayish region (G.R.), dark region (D.R.) and bright region (B.R.), in the pool. The Al3Ni and Al3Ni2 compounds appear in the G.R. and D.R., respectively. The Al-Ni-Cr amorphous structure can be observed in the B.R. The hardness of the LSA specimens is much higher than the Al-matrix. Compared with the Al-matrix, the LSA specimens have excellent sliding wear performance. They have lower friction coefficient and wear rate. The critical temperature of sliding wear resistance of LSA specimen is higher than that of Al-matrix by about 50 degrees C. The stress relief during thermal treatment will slightly reduce the hardness and the wear resistance of LSA specimens, especially at testing temperature > 200 degrees C. (c) 2006 Elsevier B.V. All rights reserved.