The V-shaped pier rigid frame bridge is a multiple statically indeterminate structure with the consolidation of the pier beam foundation, and the secondary internal force effect of the triangular rigid frame area rigidly connected by the V pier and the No.0 block is significant under the action of temperature and humidity. Therefore, taking the Gunnong Bridge in Myanmar as the engineering background, by establishing the finite element model of the whole bridge space bar system and the local solid model of the triangular rigid frame area to study the sensitivity of the three most important ambient factors of temperature, humidity, and wind speed to the hygrothermal effect of the triangular rigid frame area of the V-shaped pier rigid frame bridge. The results show that the hygrothermal stress of box girder and V pier is linearly correlated with temperature and relative humidity, and nonlinearly correlated with wind speed. Under the influence of temperature, wind speed and relative humidity, the hygrothermal stress at the junction of V pier river water and air is greater than that at the upper and lower roots of V pier. The sensitivity of structural hygrothermal stress to temperature and relative humidity is constant, and the sensitivity to wind speed is linear negative correlation. When the wind speed is less than 6m/s, the sensitivity of wind speed is much greater than that of temperature and relative humidity.