Temperature efects that arise in bridges exposed to the environmental variables are not easily estimated．Based on the Mei Jing Bridge supervision work，the temperature field and the strain field of the box beam are measured on site by means of“Time-Temperature-Deformation-Stress”．It simulated the temperature field with software MIDAS CIVIL and vertified the accuracy of results．By measuring and analysing the difenrences between the theoretical value and the actual values，the temperature effects are better controlled．It provides the basis for real-time correction of elevation of the main beam in Construction Monitoring，and selects the appropriate temperature for the PC continuous box girder bridge closure．