Through high-speed continuous erosion test system, high-speed sand-dust erosion tests of stainless steel specimens with or without TiN/Ti strength and tough coating were carried out at different impact angles and sand supplies, and the mass erosion rates of specimens were obtained. The surface and cross-sectional damage morphology of the coating were observed by scanning electron microscopy (SEM), and the failure mechanism of TiN/Ti coatings under different impact conditions was analyzed. The results show that the mass erosion rate of TiN/Ti coatings increases with the increase of impact angle and sand supply. At low impact angle, the cutting action of sand particles is the main reason for the spalling of coatings; at high impact angle, the crack initiation and propagation caused by sand-dust impact lead to massive fragmentation and spalling of coatings. TiN/Ti coating can significantly improve the erosion resistance of stainless steel, especially at low impact angle.At low impact angle, the erosion resistance of stainless steel with coating can be increased by about 5 times, and at high impact angle it can be increased by about 2 times.