Abstract: Activated carbon with high specific surface area was prepared from coconut shell charcoal(CsAC), the structural properties of which were measured. The electrochemical performances of electric double-layer capacitor (EDLC) with CsAC as electrode material were investigated, including cyclic voltammetric and constant current charge/discharge properties. Results showed that EDLC had good charge/discharge performance and the specific capacitance of CsAC reached 164 F/g. Adsorption isotherms of NH3, CO2, CH4, N2, O2 and H2 on CsAC were measured at 298K. Considerable difference among the adsorption capacities toward different gases was observed and NH3 was adsorbed much more than CO2, CH4, N2, O2 and H2. According to adsorption amount ratio of two gases, it was concluded that CsAC was a very good adsorbent for the separation of NH3 from its mixtures such as NH3/N2,NH3/O2 and NH3/air. CsAC was also suitable for the separation of NH3 from its mixture of CH4,as well as for the separation of CO2 from its mixtures of O2 or N2 or both.