U-tube heat exchanger is generally selected and used in the cased there is bigger the average wall temperature of the metal pipe and shell side or the medium in shell side is easy to scale and need to be cleaned ,especially the clean and difficult to scale of high temperature and pressure, corrosive materials go through tube side. A lot of key equipments select titanium in order to avoid the medium corrosion. The design of titanium U-tube heat exchanger was introduced in detail, mainly including the selection of materials, structure design, strength design, requirements of manufacturing and inspection, etc..