The key factors are stress problems and thermal problems，which influence the life and long-term reliable operation for magnetic drive pumps. At the same time, they are also the difficulty in the design of magnetic pumps. The design scheme was given to solve the problems stress and thermal according to condition of application practice for the type of magnetic drive pumps of 100CQY-120. The industrial operation proves that the scheme is reliable and correct, and the designed pump operates smoothly and reliably in performance. 