Abstract: As core elements, gears are widely applied in aircrafts, large warships, advanced railway vehicles, electric automobiles, intelligent robots and power equipment. Since surface wear is a main failure mode of gear drives, the prediction methods and suppression techniques for tooth wear loss should be performed by both theoretical analysis and measuring techniques. According to adhesive wear, fatigue wear, energy wear theories, and material wear rate, different wear models and calculation methods for tooth surfaces were investigated first. Then, three tests (as equivalent, scale or real specimen in use) applied in investigation of gear wear, and weighing method, surface profiler, ferrography and spectral analysis were discussed. Results show that an available wear model and prediction method should be chosen according to the materials-structural characteristics, working conditions, failure modes of a gear drive, while the theoretical analysis, numerical simulation are combined with measuring techniques for determining the tooth wear loss. As the traditional hardened gears and lubrication techniques are improved, solid-film lubrication, wear-resistance and friction-reduction coating, and compound surface reinforcement are beneficial for the antiwear design of high-performance gears.