The running-in tribological behavior of the electrodeposited nano-SiO 2 /Ni composite coatings is investigated using an M-200 block-on-wheel friction and wear tester. The results show that the electrodeposited nano-SiO 2 /Ni composite coatings exhibit good wear resistance in the running-in period. With increasing nano-SiO 2 particle content in the electrodeposition plating solution, the wear resistance of the composite coatings are first improved and then decreased slightly, and the friction coefficient decreases first and then increased. If the nano-SiO 2 particle content in electrodeposition plating solution is 10g/L, the composite coatings show the best wear resistance.