The invention discloses a method for improving the bonding strength of an interface between a hard coating and a substrate. The method is implemented by treating the hard coating/substrate compound system at the low temperature or ultralow temperature of between 50 DEG C and 273 DEG C below zero for 5-48 hours. The hard coating comprises nitride coatings such as TiN, CrN, TiAlN, TiSiN, CrAlTiN, BN and the like, C coatings such as diamond, diamond-like carbon and the like, and carbide coatings such as TiC, WC and the like. Due to the adoption of the method, the bonding strength of the interface between the coating and the substrate can be raised by 10-50 percent, and deterioration of the performance of the substrate or coating can be avoided by adopting of the conventional high-temperature annealing method; and meanwhile, low-temperature or ultralow-temperature treatment cost is low, and the method is suitable for various coatings/substrate compound systems.