Abstract: Directing at low temperature water bath in the real operation of water jacket heater used in the petroleum industry, this paper analyzes the causes of low water temperature phenomenon using heat transfer model of water jacket heater, and puts forth the relevant solution program. Proper heat transfer area of heat exchange bundle is applied in the design of water jacket heater, making water bath temperatures reach the theoretical design level as much as possible to realize optimum design of water jacket heater. It puts forward the standard of evaluating water jacket heater design optimization using water boiling time, that is, the mass of the water as heat medium is kept at the minimum, and water boiling time is limited within 0.5~2 hours on the condition that proper heat transfer area of heat exchange bundle is ensured. Optimization measures can effectively reduce manufacturing and running costs of the heater type and fulfill the goal of energy saving and emission reduction.