Longtan River Bridge, which the length of the main span is 200m and the height of the main pier is 178m, is a long span continuous rigid frame bridge. Temperature field of the box-pier and the box-girder due to solar radiation were measured. Regression analysis of the temperature difference has been done by using the least square method, and the fitting curve of the vertical and the transverse non-linear temperature difference distribution of box-pier and box-girder are o...