3wt% AlB2/6061 composites were in-situ synthesized by molten salt method using Al-KBF4 as reaction system. Compared with 6061 matrix, effects of AlB2 particles on the hardness and wear resistance of the composites were studied. The results show that regular hexagonal AlB2 particles with the size of 0.5~2.0 μm can be directly in-situ synthesized in 6061 matrix. After T6 heat treatment, the hardness of 3wt%AlB2/6061 composites is HB 119.1, which is 2657% higher than that of 6061 matrix. The specific wear rate of the composites is 1.83×10-8 kg·N-1·m-1, which is 17.94% lower than that of 6061 matrix. Due to good enough wettability and high interface bonding strength between AlB2 particles and the matrix, and high hardness of the particles, the particles can play a bearing role, then reduce the contact area between the composites and the wear-resistant material during wear, thus wear resistance of the composites is improved. The wear mechanism of the composites is mainly abrasive wear and adhesive wear. The average friction coefficient of the composites is 0.235, which is 17.54% lower than that of 6061 matrix.