Multi-objective fuzzy matter element method was put forward to optimize the sensor quantity. Fuzzy matter element matrix was constructed by means of center effect measure, and the monitoring point was optimized according to the comprehensive correlative degree. Twenty-seven sensors was reduced to 7 in the refrigerator car, which reduced the costs of cold-chain transportation. The statistical analysis method and the temperature field analysis were applied to validate the rationality of the optimization algorithm. The measurement data of sensors had more than 95% of confidence level and the similarity rate of temperature field distribution between before and after optimization reached over 90%, which achieved the dual requirements of cost savings and accurate monitoring in cold chain transportation.