Abstract: Based on the theory of heat convection, the structure of a tubular sterilizer with normal atom-spheric pressure, its heat transferring pattern and the calculation method of its heat transfer coefficient were studied. The design of the sterilizer was verified with empirical data and probative tests. The calculation methods used are correct and reliable,and can be applied in the design of sterilizers or heat exchangers of this kind,and a computer programme was developed for the calculation. The sterilizer designed can be u-tilized in the milk pasteurization operation reliably,and is cheap,simple in structure, easy for operation and maintenance especially, suitable for small sized dairy or related enterprises to use.