Guss asphalt used in pavement of a steel deck bridge may cause severe stress and displacement on the bridge as it is treated using very high temperatures ranging from 220oC to 260cC. Therefore, it is critical to estimate the thermal effect of Guss asphalt on the steel deck bridge before the width and pattern of the unit portion are decided in order to minimize impact. In this study, we have conducted a series of numerical analysis of the upper road of Youngjong Grand Bridge, verified the feasibility of numerical value analysis by comparing the results with the data measured, and studied the thermal effects of Guss asphalt on the steel deck bridge according to temperature changes.