Abstract:With the low-end market to high-end market transformation of automobile industry in China, the precision requirement of auto parts is also increased to ensure the mechanical and physical properties. Coordination characteristics among assembly parts is also facing new requirements, for example, the relative sliding between the synchronizer gear hub and tooth sleeve should be smooth, without clamping stagnation phenomenon, to ensure the smooth shifting in the car running process. In order to meet this requirement, the size precision of synchronizer gear hub and tooth sleeve, such as tooth shape, tooth and pitch error, has to be controlled precisely to ensure the appropriate assembly clearance and its uniformity. It often needs more than once experiments to meet the requirements of product design, leading to waste of resources, increased costs and long cycle of products, and then the competitiveness of products is greatly weakened. Using UG_CAE technique, the influence of shaping modes on the deformation of synchronizer gear hub was expected, the product development cycle was shortened, and the product quality was ensured.