Low fracturing efficiency and high permeability filtration present substantial challenges during the fracturing development of coalbed methane (CBM), significantly hindering its efficient exploitation. In this study, a cross-linker featuring specific polar functional groups on its side chains was synthesized, and a multi-functional coupling evaluation apparatus was developed to systematically investigate the performance characteristics of water-based fracturing fluids. Furthermore, molecular dynamics simulations were employed to elucidate the microscopic mechanisms by which the modified cross-linkers and various external factors influence CBM extraction efficiency. The results indicated that the modified water-based fracturing fluid enhances fracture propagation and reduces fluid filtration into the reservoir. Increasing the concentration of the cross-linker (0wt% to 0.3wt%) improves both gas production efficiency and fracture expansion capacity (20m of crack length to 36m). Conversely, elevated reservoir temperatures (383K to 433K) markedly decrease gas recovery efficiency while significantly increasing fluid seepage (5.8ml to 7.5ml) and expansion capacity (26m of crack length to 42m). In contrast, higher reservoir pressure demonstrates an opposite trend by enhancing extraction efficiency and mitigating fluid filtration. The alteration of chemical bonding interactions between fluid molecules is identified as a key microscopic mechanism influencing CBM development, thereby offering a theoretical foundation for optimizing water-based fracturing strategies in low-permeability coal reservoirs.