UiO-66-NH2@GO nanoparticles were synthesized by growing UiO-66-NH2 on graphene oxide (GO) nanosheets. The obtained nanoparticles were incorporated in polyimide (PI) matrix to improve the CO2 separation performance. The crystalline structure, interaction between UiO-66-NH2 and GO and the dispersion of UiO-66-NH2@GO were characterized by various techniques. Owning to the interaction between UiO-66-NH2 and GO, UiO-66-NH2 nanocrystals were well-anchored on GO sheets and the size was tailored. Also, it can be found that the high-aspect GO nanosheets in polymer matrix improved the dispersion of UiO-66-NH2 nanoparticles. The high porosity of UiO-66-NH2@GO and inherent adsorption property to CO2 significantly enhanced the gas separation performance of composite membranes compared to pristine PI membrane. The developed UN@GO-PI mixed matrix membrane with 5 wt% of UiO-66-NH2@GO loading showed excellent and stable CO2/N-2 separation performance with the CO2 permeability of 7.28 Barrer and the CO2/N-2 selectivity of 52.