In order to deal with some problems such as the high cost of devices, the low efficiency for forming and the complicated process on the operation during the process of bimetallic tube hydroforming, a new compound forming method that is also called liquid impact forming and which is based on the stamping and tube hydroforming technology was proposed. Firstly, basic principle of liquid impact forming was introduced. Secondly, four simple and practical installation of liquid impact forming, including molding units, axial feed sections, control systems and secondary elements, were introduced. In addition,the forcing states for bimetallic tube were analyzed. At last, the stress and the strain whether in or outside the tubes of bimetallic tube were both discussed applying the elasticityplasticity theory. At the same time, the criterion of internal pressure pi was obtained by using the relation of deformed compatibility. The liquid impact forming technology will provide not only a new scientific basis but also technical support for bimetallic tube forming.