The invention discloses a preparation method of a zero-pollution coal gangue pavement base material, which comprises the following steps: firstly, taking tunneling gangue and/or washing gangue, and crushing and screening by adopting a wet-type selective crushing system to obtain full-size-grade coal gangue granules; then, carrying out single-package coating by adopting a sodium silicate solution; then carrying out double coating by adopting cement-based cementing material powder; further, screening to obtain double-packed coal gangue coarse aggregate and double-packed coal gangue fine aggregate; and finally, mixing the double-packed coal gangue coarse aggregate, the double-packed coal gangue fine aggregate, an inorganic binder, a curing agent and water to obtain the zero-pollution coal gangue pavement base material. According to the preparation method, the release and migration of toxic and harmful components in the coal gangue are completely eradicated, the pollution to the atmospheric environment and water environment of a workshop is eliminated, the environmental safety and human health in the whole preparation process of the coal gangue pavement base material are realized, the pavement performance of the coal gangue aggregate is improved, and the range of the road coal gangue is expanded.