Taking the heat transfer oil heat exchanger in the process of preparing polyethylene in the petrochemical industry as the research object,the heat transfer process between the heat exchanger shell and tube medium was numerically simulated through the method of flow field simulation and the experimental verification was carried out,and the influences law of the different structural parameters of the new type baffle on the heat transfer coefficient of the heat exchanger shell and the comprehensive indexes were discussed.The method of orthogonal experimental design was used to optimize the structural parameters of the new type of folding plate and the regression model of the optimization target was obtained,so as to get the optimal structural size of the new type baffle.The results show that the optimal structural parameters of the new type baffle heat exchanger are H/D=0.633, W/D=0.595 and L/s=0.347;the comprehensive index of the optimized new folding plate heat exchanger is improved by 25.979 9（16%） compared with the initial value,the heat transfer performance of the heat transfer oil heat exchanger is obviously improved.