The low temperature viscoelastic characteristics of asphalt binder were measured using bending beam rheometer（BBR）. The general Maxwell model was adopted as the constitutive model to describe the viscoelastic behavior. Thermal stress of 50# asphalt binder under different temperature decrease rates was calculated based on viscoelastic theory. Other three types of asphalt binders, 70#，90# and SBS modified asphalt binder, were also tested and analyzed for comparison. It has been found that at the same temperature decrease rate, SBS modified asphalt binder has the lowest thermal stress while 50# asphalt binder has the greatest. As temperature decrease rate increases, the thermal stress increases significantly. The temperature effect must be considered in field application when using low penetration asphalt binder and the thermal stress should be taken into consideration for the pavement structure.