High-temperature oxidation is a serious problem for several materials during their application in aggressive environments, such as high temperatures, high-speed machining, and corrosive environments. This research was conducted to analyze the effect of high-temperature oxidation on the surface morphology of the Ni-AlN-TiN/Si3N4 composite coating. The coatings were electrodeposited at a current of 5 me for 15 minutes and various electrodeposition temperatures of 35°C, 40°C, and 45°C. This composite coating was formed on tungsten carbide substrates with the electrolyte solution consisting of 6 g/L AlN, 6 g/L TiN, 40 g/L H3BO3, 0.6 g/L Si3N4, 0.17 M NiCl2.6H2O, 0.38 M NiSO4.6H2O, and 0.6 g/L Sodium Dodecyl Sulfate. The high-temperature oxidation process was carried out at a temperature of 700°C for 2 hours in the furnace. The surface morphology was characterized by using Scanning Electron Microscopy (SEM). The results showed that the surface morphology of the Ni-AlN-TiN/Si3N4 composite coating deposited at a temperature of 40°C had a scaled growth, reduced cracks, and reduced pore. It was due to the effect of high-temperature treatment.