The double cross-linked network structure was formed by combining polyvinyl alcohol (PVA) and sodium alginate (SA) with boric acid (H3BO3) and calcium chloride (CaCl2), respectively. Potassium humate (KHA) and calcium-based montmorillonite (MMT) nanoparticles were loaded in it, so a double cross-linked gel beads (PVA/SA/KHA/MMT) were successfully prepared. The gel beads demonstrated excellent removal efficiency for methylene blue (MB) dye and Pb(Ⅱ). The physical and chemical properties of gel beads were systematically characterized by FTIR, XRD, TGA, SEM-EDS, zeta and BET. In addition, the adsorption process follows the pseudo-second-order kinetic model, and the experimental data was in good agreement with the Langmuir model. At 298 K, the maximum adsorption capacity (Qm) values of MB and Pb(Ⅱ) were 725.42 and 375.64 mg/g, respectively. The thermodynamic results showed that the adsorption process of the gel beads was spontaneous, endothermic, and driven by the increase of the overall entropy of the system. Meanwhile, the results of FTIR and XPS indicated that the adsorption mechanism of Pb(Ⅱ) was mainly through the chelation of carboxyl groups, while the adsorption of MB occurs through hydrogen bonding and electrostatic interaction. Furthermore, PVA/SA/KHA/MMT gel beads show excellent adsorption selectivity for MB and Pb(Ⅱ). Notably, it still showed a higher removal efficiency for (MB) and Pb(Ⅱ) after 5 cycles.