Abstract: heat treatment process is an important technical link in the manufacture of various mechanical products. After heating, the workpiece has been cooled by quenching medium to meet the process hardness requirements, however, the cooling performance of the quenching medium directly determines the internal quality of the workpiece and the important role of controlling the deformation of the part during the quenching process, the quenching medium absorbs a large amount of heat in the continuous production process to rapidly reduce the temperature of the workpiece, and its temperature is gradually increasing. Most of the existing temperature control methods are passive or equipped with cooling towers to lower the temperature. The product quality fluctuates greatly after passive continuous production, firms closer to residential areas are thus constrained in their production. In view of these factors, the existing technical scheme of quenching oil tank is improved. The environment-friendly quench oil temperature control system for quench oil tank has been verified by field engineering. By adding cooling module and temperature detection and external cooling water circulating mechanism, the temperature rise of quench oil can be effectively reduced and the volatile oil and gas can be reduced, the invention reduces the disadvantage of high noise of the original equipment, stabilizes the quenching performance of the quenching oil, and has the advantages of simple operation, low noise, high performance-price ratio and remarkable energy-saving and environmental protection effect.