The invention relates to a process for determining the thickness of a non equal thickness pipe plate, which mainly solves the problem existing in the prior art that a complete calculation method for the non equal thickness pipe plate does not exist. The invention divides the non equal thickness pipe plate into a distributing region and a non support region, wherein the thickness of the distributing region is determined according to a pure thin pipe plate, and the thickness of the non support region is determined according to the process which comprises viewing the distributing region as the rigidity fixation, giving the non support region the equal distribution loads, and axially moving the external shaft thereof, wherein the technical scheme of determining the thickness thereof accordingto the rigidity of the non support region well solves the problem, and the process can be used in the design and production of thin pipe plates for fixing a pipe plate exchanger.