The joint of the cylinder nozzle and jacket is one of the key components of the heat exchanger, which has much effect on the stress of the equipment.APDL language was applied to establish the structural analysis model of the bottom channel with jacket and insulation.According to the operation conditions, the temperature and pressure were loaded to obtain the stress intensity and fatigue life at different angles of jacketed flanging structure.The recommended flanging angle of jacket was given after checking and comparing the stress intensity and the fatigue life of the equipment.The result provides an effect reference to the design of the joint structure and has a certain engineering application signifigance.