The work aims to improve wear resistance of coating by further improving microhardness of Ni-TiN nano composite coatings electrodeposited by pulse-ultrasound. Surface morphology, microstructure, microhardness and wear resistance of Ni-TiN nano composite coatings were detected using scanning electron microscopy, X-ray diffractometer, microhardness tester and friction and wear instrument after heat treatment at temperature 200~600 ℃. Effects of heat treatment manner on morphology, microstructure, microhardness and wear resistance of the composite coatings were studied. After heat treatment at 300 ℃ for 1.5 h, the most flat and smooth coating surface was obtained. With the increase of heat treatment temperature, grains of the coating grew and its surface roughness decreased. Meanwhile, the coating began to transform from amorphous to crystalline state. In addition, the coating hardness was the maximum, 815HV. After heat treatment at 600 ℃ for 1.5 h, the wear resistance of the coating was the best, and the abrasion loss was 13.2 mg. The hardness of the coating is improved to a certain extent after heat treatment since TiN nano particles mainly has dispersion strengthening effect and fine crystal strengthening effect. The wear resistance is effectively improved since coating toughness as well as adhesion between the coating and substrate are improved, and a dense oxide film is formed.