Liquid level recirculation control is an important means of process control, which plays a key role in the production process of rectification process, absorption and regeneration and liquid level maintenance of the vessel.The phenomenon of medium temperature rise which occurs in the top reflux system of MDEA regeneration tower is introduced.The reason of medium temperature rise is systematically analyzed from the perspective of energy balance.In the system, the source of medium temperature rise is determined, and the maximum value of temperature rise is calculated.In order to maintain the liquid level smoothly in the separation tank, the design optimization measures and suggestions are proposed,which has guiding significance for the engineering design and the operation of liquid level control in the similar system.