At present, light weight has become an important trend of modern cars. Compared to conventional stamping technology,using hydroforming technology, weights of the car engine bracket, radiator brackets and other components reduce 30% or so. And hydroforming technology has many technical advantages and economic advantages, such as rigidity and strength of the products are improved significantly, production costs are reduced. Combined with practical work experience, from the mechanism, process characteristics and failure mode of the hydroforming technology, taking car engine bracket as the main object, by the corresponding experiments,the material properties changes in hydroforming process of the car engine bracket were explored, to arrive at the points that should be focused in the application of the hydroforming technology.