In order to solve the optimization problem of ship waste heat utilization system, the modeling and optimization method of ship waste heat utilization system based on genetic algorithm and sensing is proposed. The 6S50ME-C8.2 volume method model was established based on Matlab/Simulink simulation platform. According to the test data of the 6S50ME-C8.2 diesel engine, the simulation value is very close to the test value, which verifies the accuracy of the simulation model. The experimental results show that the thermal efficiency of high-power medium and low-speed two-stroke diesel engines is high, the exhaust temperature of the main engine is generally maintained at about 230°C, and the energy content of exhaust gas is relatively low. If no other measures are taken, the waste gas is directly channeled into the waste heat boiler, which cannot effectively recover the heat in the waste gas. Conclusion. The model can well simulate the actual working condition of the diesel engine, and the exhaust temperature has reached 298°C. The energy quality of waste gas at the inlet of the waste heat boiler is improved to meet the requirements of the waste heat recovery system.