In order to improve the crack durability of the cement-stabilized gravel base and achieve the goal of long service life of the pavement, different amounts of polypropylene fiber were added to the water-stabilized gravel base, and the optimal polypropylene fiber content was determined by testing the splitting tensile strength test of the specimen at different curing ages. Then, the effects of polypropylene fiber incorporation on compressive strength, splitting tensile strength and flexural tensile strength were analyzed by macroscopic mechanical property test, and finally the semicircular bending test was carried out on the two groups of specimens to obtain their displacement time curves, and the full-field strain test system (DIC) was used to monitor and compare the loading process in the full time domain. The test results show that the optimal content of polypropylene fiber in the water-stabilized gravel base is 0.1%, and the incorporation of polypropylene fiber can improve the macroscopic mechanical properties of the water-stabilized base, delay the development of cracks in the water-stabilized base by playing its own bridging role, and reduce the strain concentration and displacement surge through stress transmission.