Mechanochemical synthesis, driven the chemical transformation by mechanical force, has been a rapid and efficient strategy to prepare metal organic frameworks (MOFs). In this work, a liquid-assisted mechanochemical method has been successfully applied to the synthesis of copper based MOF-505. The crystallinity and porosity of MOF-505 were investigated by adjusting the synthesis parameters, such as added solvent (type and amount) and grinding time. Results showed that the type and amount of added solvent were crucial parameters for the mechanochemical synthesis of MOF-505. Furthermore, the optimizations of MOF-505 synthesis were carried out: grinding Cu(OAc)(2)center dot H2O and H(4)bptc as starting materials for 80 min with 0.4 mL of DMF assisted, giving MOF-505-K with Brunauer-Emmett-Teller (BET) surface area of 977 m(2)/g. Meanwhile, MOF-505-K had moderate CO2 adsorption capacity of 2.01 mmol/g at 298 K and 100 kPa. The adsorptive selectivity determined from ideal adsorbed solution theory (LAST) indicated that MOF-505-K had high CO2/N-2 and CO2/CH4 selectivities (26.6 and 5.5) at 298 K. Highly efficient mechanochemical synthesis of MOF-505 provides the promise to facilitate the industrial application of CO2 capture.