Fixed tube-sheet heat exchanger is the most widely used of a heat transfer equipment currently, as a standard heat transfer equipment. Its Bundle tubes consists with a number of tubes, the tubes fixed to the tube plate,wich is join together with shell. In order to increase fluid flow rate in the pipe outer space, to improve its heat transfer, Multi-block Baffled boards were installed in cylinder. It has Single-tube and Multi-tube.It has many advantages,for example: the structure is simple and compact, low cost and wide range of applications.