Ni-P composite coatings with various contents of Al₂O₃ particles were prepared by using electroless plating technique and the tribological properties of the coatings were evaluated by a ball-on-disc wear instrument. The morphology, microstructure and chemical composition of the coatings and the counterpart balls were characterized by scanning electron microscopy (SEM), optical microscopy (OM), energy disperse spectrum (EDS), and X-ray diffraction (XRD) technique, and the wear mechanisms were discussed. The results show that the maximum content of Al₂O₃ in the composite coating is about 34.7 wt.%, the phosphorus content of the coatings decreases greatly, and the Ni-P matrix of the composite coatings remain amorphous. The friction coefficient of the coatings is about 0.49–0.58 and higher than that of Ni-P coating. With the increase of Al₂O₃ content in the coatings, the friction coefficient decreases at first and increases later, the micro-hardness of the coatings linearly increases from 502 to 764, and the wear rate of the coatings monotonously decreases from 1.2×10_-14 m₃.N_-1m_-1 to 3.2×10_-15 m₃.N_-1m_-1, and the major wear mechanism of the coatings changes from adhesive wear to abrasive wear.