Poly(styrene-b-butadiene-b-styrene) triblock copolymer (SBS) crosslinked membranes containing poly(dimethylsiloxane-co-methylhydrosiloxane) (PDMS-co-PMHS) were prepared by hydrosilylation reaction toward CH4/N-2 separation. The effect of an additive amount of PDMS-co-PMHS on the structure, morphology, and thermodynamic stability of crosslinked membranes were investigated by using FT-IR, SEM and TGA. Soxhlet extraction experiments were also performed to explore the crosslinking degree of membranes. In this work, the single-gas permeability of CH4 and N-2 was measured using the constant volume variable pressure method. Our experimental results showed that crosslinked membranes can significantly enhance CH4 permeability with increasing PDMS-co-PMHS content, whereas the CH4/N-2 selectivity remains unchanged. Among these crosslinked membranes, the SBS-c-PDMS-co-PMHS-70 membrane exhibited optimal CH4 permeability at room temperature and the pressure of 1 bar. Specifically, the CH4 permeability was > 10 -folds higher than that of the SBS membranes (37.6 barrer versus 443.6 barrer). Moreover, investigation of the effect of test temperature on the gas permeation of crosslinked membranes revealed a preferable CH4 permeability at 55 degrees C and 1 bar, at which the CH4 permeability reaches 679.2 barrer without a substantial compromise in selectivity.