Due to its high gravity and weak torsional resistance，the miter gate will produce torsional deformation when hanging naturally. As a steel member，the miter gate is in an open-air environment，and its temperature is much higher than the ambient temperature under the direct action of solar radiation in summer，which will aggravate the structural deformation of the miter gate. To quantify the influence of solar radiation on the structure of the miter gate，based on ASHRAE clear sky model，the temperature field，deformation and stress distribution of the miter gate are simulated by ANSYS finite element software. The results show that：1）Under the action of solar radiation，the temperature field with uniform spatial distribution is formed，and the maximum temperature reaches 67 ℃ at about 3 pm. 2）The deformation and stress of the main components of the gate still meet the standard requirements under the maximum temperature load. The deformation of the gate gradually increases with the temperature rise，and the displacement of the miter column and the deformation of the back tie rod increase by 1～3 times，which should be paid attention to in practical engineering design.