It is critical to enhance further the stability and adsorption selectivity of MOFs for promoting applications of MOFs. Herein, we proposed an effective bifunctional SBU-tuning strategy to synthesize novel Pyr(1/3)@Cu-BTC for the separation of propylene/propane. Pyrg Cu-BTC was synthesized by grafting of pyrrole onto Cu-BTC. Its water vapor stability and separation property were then examined. The resulting Pyr(1/3)@Cu-BTC showed not only enhanced water vapor stability but also superhigh C3H6 adsorption capacity as well as C3H6/C3H8 selectivity at 1 bar and 298 K, reaching 7.60 mmol/g and 8.3 separately, much higher than most MOFs. Experiments of water vapor stability indicated that after being placed under humid air (RH of 55%) for 20 days, Pyr(1/3)@Cu-BTC still retained its crystalline structure. The application of the fixed bed of Py-1/3@Cu-BTC could completely separate C3H6 and C3H8 from their mixture at ambient conditions. Pyr(1/3)@Cu-BTC is promising for the separation of propylene/propane or propylene recovery from dry gas.