In order to analyze and study the uneven temperature distribution of long-span bridge in the operation process, taking a 160-m high-pier long-span continuous rigid-frame bridge as the background, by considering the factors of sun shining, convective heat exchange, radiation heat transfer and daily atmospheric temperature variation in summer and winter, the three-dimensional temperature field of the whole bridge is simulated and analyzed through ANSYS software. The analysis result show that the vertical temperature gradient of concrete bridge in General Code for Design of Highway Bridges and Culverts JTG D60—2015 is smaller than that of the bridges in the actual operation. The vertical temperature gradient value can be increased as appropriately in the future design for the mountainous areas with larger temperature difference between day and night.