In order to improve the road performance of waterborne polyurethane, the low temperature performance, water resistance and dynamic thermodynamic properties of modified waterborne polyurethane binders with different contents were studied, as well as the microscopic analysis of infrared spectroscopy, particle size test and fluorescence microscope, the modification effect and modification mechanism of modified waterborne binder were discussed and analyzed. After modified by water-based resin modifier, the strength, low-temperature performance, water resistance and thermomechanical properties of the water-based binder are significantly improved, and the optimal admixture dosage of 15% exists at the same time. Three kinds of microscopic analysis prove each other that new functional groups and intermolecular hydrogen bonds will be formed between waterborne resin modifier and waterborne polyurethane, which will increase the crosslinking density and change the molecular structure from linear structure to network structure. However, excessive dosage will lead to the increase of particle size and agglomeration effect of binder, which will adversely affect the mechanical properties of binder.