The paper presents the basic principle and application of High Velocity Arc Spraying technique. Through adopting convergent-divergent nozzle, air circulation cooling and computer aided design technique, particle velocity was enhanced, which surpasses velocity of sound, and atomization effect was improved, so HVAS fabricated high quality coating. Experiment results show that HVAS has high particle velocity, high atomization effect, high bond strength and low porosity. Average velocity of atomized Aluminum particle is 373m/s. Bond strength, porosity and average particle size of 3Cr13 coating are 60MPa, 0.9% and 4.32 m respectively. For high coating quality, HVAS is widely used in maintenance, corrosion resistance and surface strengthening.