To investigate the influence mechanism of fiber incorporation on the compaction characteristics of asphalt mixtures, six types of typical road fibers (polyester fiber, polyacrylonitrile fiber, aramid fiber, basalt fiber, polypropylene fiber, and polyvinyl alcohol fiber) were selected in this paper, and gyratory compaction tests were conducted based on AC-20 graded mixtures. The compaction coefficient (a larger compaction coefficient indicates easier compaction) was used as the core evaluation index. The results indicate that the elastic modulus of the fiber is the key influencing factor. When the fiber modulus is 50% lower than the aggregate modulus (such as polyester fiber and polyacrylonitrile fiber), the compaction coefficient decreases significantly (4.43% for the blank group, 3.94% for the polyester fiber, and 4.04% for the polyacrylonitrile fiber), and the compaction difficulty increases; when the fiber modulus is close to or higher than the aggregate modulus (such as 4.41% for the aramid fiber and 4.45% for the basalt fiber), the compaction performance does not change significantly. The influence of fiber length is regulated by the modulus: Increasing the length of low-modulus fibers helps improve the compaction coefficient (such as polyacrylonitrile fiber), while reducing the length of high-modulus fibers is beneficial to compaction (such as aramid fiber). A threshold effect exists in fiber dosage; the compaction coefficient changes nonlinearly with the dosage and reaches a peak at a specific dosage. The construction compaction process is required to be designed differentially; the order of the number of compaction passes required for the mixture to reach the target void content of 4% is polyvinyl alcohol fiber < basalt fiber < polypropylene fiber < aramid fiber < blank group < polyacrylonitrile fiber < polyester fiber. Except for the polyester fiber and polyacrylonitrile fiber, the other fibers have no significant effect on the conventional compaction process.