To reveal the premature failure mechanism of polyurethane binder， it is used to optimize the formula and construction process. In this paper， by analyzing tensile strength， shear strength， bond strength， elongation at break， micro-morphology， and functional groups， the failure mechanism of polyurethane binder was summarized. The results showed that after 480 h aging， the elongation at break of hydrothermal aging was 2.44 times that of thermal oxygen aging， and the reduction ratio of bond strength and shear strength were 4.01 times and 8.95 times that of thermal oxygen aging， respectively. Moreover， the weakening effect of ultraviolet aging on tensile strength was much greater than the increase of strength after curing， and its aging rate was accelerated， resulting in an accelerated decrease in tensile strength. In addition， during the pavement construction process， it was necessary to ensure that the moisture content of cement pavement should be less than 4% as much as possible. Construction can continue after drying for about 24 h after rainfall. When the construction period is tight， a high-power floor-standing industrial fan or infrared heating truck can be used to reduce the water content of the road surface so as to ensure the construction quality of the polyurethane binder.