Tube Hydroforming technology main applied for manufacturing the hollow structure parts of transportation, and those products has several advantages, such as light weight、stiffness better、one piece, etc. The T-shape tube is the basic product of applied for Tube Hydrofroming, and it is also open sesame to studying tube hydroforming. Today, the manufactures in Taiwan have a lot of experiences and technology to manufacture the T-shape tube. One the fundamental, it must be prompted the factories upgrading and introduce them into the field of Tube Hydroforming. Computer simulation is used in the hydroforming process to reduce the cost of experiment investigations and the tryout process. The paper studies the formability of the T-shape tube, and describes the simulation process of tube hydroforming. It can give the related industry for the reference.