A versatile microporous metal-organic framework (MOF), {[Cu(TIA)]·1.5CH3OH}n (Cu-1), was successfully obtained via the solvothermal reaction of cuprous(II) salt with the bifunctional ligand 3-(1H-1,2,4-triazol-1-yl)isophthalic acid. Single-crystal X-ray diffraction studies indicate that Cu-1 contains an apo three-dimensional skeleton and two types of one-dimensional channels. The framework of Cu-1 has excellent acid-alkali resistance and thermal stability, which is stable in a pH = 2-13 aqueous solution and an 260 °C air environment. In addition, the microporous copper MOF shows very high uptakes of CO2 (180 cm3·g-1) and C2H2 (113 cm3·g-1) at 273 K and displays excellent adsorption selectivity for small molecular gases. The ideal adsorbed solution theory selectivity values for C2H2/C2H4, CO2/CH4, and CO2/N2 are 2, 9, and 22 at 298 K, respectively. At the same time, breakthrough experiments for CO2/CH4, CO2/N2, and C2H2/C2H4 were further conducted to verify the efficient separation performances.