The solid waste coal gangue produced in the process of coal mining and washing and the discharge of Pb(II) from industrial wastewater will bring great harm to the ecosystem and human health, and it is of great significance to study the efficient removal method of Pb(II) and the rational utilization of coal gangue for ecological and environmental protection. In this paper, a low-cost aminothiol difunctional modified coal gangue (CG-SHNH) composite was prepared by grafting (3-mercaptopropyl)trimethoxysilane (MPTMS) and 3-aminopropyltriethoxysilane (APTES) with coal gangue. The physical and chemical properties of adsorbed materials can be comprehensively analyzed by means of XRD, SEM-EDS, XFR, FTIR, BET, Zeta potential, etc. The FTIR results showed that new bands appeared at 2930 cm-1 and 2560 cm-1, corresponding to C-H and S-H tensile vibrations, respectively, and a new peak appeared at 3367 cm-1, which was the absorption peak of N-H bonds, indicating that there were abundant amino and sulfhydryl functional groups on the surface of CG-SHNH. The BET results showed that the average pore size of CG-SHNH increased significantly, from 17.33 nm to 24.54 nm. The adsorption performance of the prepared CG-SHNH on Pb(II) was studied, and the results showed that CG-SHNH had the best adsorption effect on Pb(II) with an adsorption capacity of 125 mg/g when the CG-SHNH input was 1 g/L, the adsorption time was 20 h, the temperature was 25 °C, the pH value was 6.6, and the initial concentration was 600 mg/L. The adsorption mechanism study showed that the amino and sulfhydryl bifunctional groups could synergistically promote the chelating adsorption of Pb(II), and CG-SHNH showed excellent adsorption capacity of heavy metal ions, and its adsorption performance was significantly higher than that of coal gangue and coal gangue grafted only with sulfhydryl group.