As oil and gas exploration and development gradually shift towards the “double depth and double high” domain characterized by deep water, deep depth, high temperature, and high pressure, downhole electronic equipment faces the threat of high-temperature failure. Based on wellbore heat transfer model and non-dominated sorting genetic algorithm, the study investigates the extent to which drilling parameters affect downhole temperature and establishes a multi-objective parameter optimization model for downhole cooling. And the following research results are obtained. Firstly, adjustable drilling parameters for downhole temperature regulation include inlet temperature, pump rate, and rotation velocity. Secondly, the sensitivity analysis of downhole temperature parameters shows that cooling capacity is in a reverse relation with formation fracture pressure, which is the direct reason for the adoption of multi-objective optimization. Thirdly, through multi-objective optimization and decision integration, the optimal combination of operational parameters for downhole cooling was determined: inlet temperature of 16.87 ℃, pump rate of 14.84 L/s, and rotation velocity of 49.35 rpm, resulting in an optimized bottomhole temperature of 133.18 ℃. In conclusion, the concept of multi-objective optimization is feasible and applicable to downhole cooling. It provides a reference for the efficient development and utilization of deepwater drilling, aids in the design and construction optimization of high-temperature, high-pressure wells, and helps prevent downhole tool failures.