Carbon dioxide(CO_2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite(TFC) hollow fiber membrane was developed by interfacial polymerization between 1,3–cyclohexanebis–methylamine(CHMA) and trimesoyl chloride(TMC). ATR-FTIR, SEM and AFM were used to characterize the active thin layer formed inside the PSf hollow fiber. The separation behavior of the CHMA-TMC/PSf membrane was scrutinized by studying various effects like feed gas pressure and temperature. Furthermore, the influence of CHMA concentration and TMC concentration on membrane morphology and performance were investigated. As a result, it was found that mutually the CHMA concentration and TMC concentration play key roles in determining membrane morphology and performance. Moreover, the CHMA-TMC/PSf composite membrane showed good CO_2/CH_4 separation performance. For CO_2/CH_4 mixture gas(30/70 by volume) test, the membrane(PD1 prepared by CHMA 1.0% and TMC 0.5%) showed a CO_2 permeance of 25 GPU and the best CO_2/CH_4 selectivity of 28 at stage cut of 0.1. The high CO_2/CH_4 separation performance of CHMA-TMC/PSf thin film composite membrane was mostly accredited to the thin film thickness and the properties of binary amino groups. Carbon dioxide (CO 2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite (TFC) hollow fiber membrane was developed by interfacial polymerization between 1,3-cyclohexanebis ATR-FTIR, SEM and AFM were used to characterize the active thin layer formed inside the PSf hollow fiber. The separation behavior of the CHMA-TMC / PSf membrane was scrutinized by studying various (CHMA) and trimesoyl chloride (TMC) effects like feed gas pressure and temperature. As a result, it was found that mutually the CHMA concentration and TMC concentration play key roles in determining membrane morphology and performance The CHMA-TMC / PSf composite membrane showed good CO_2 / CH_4 separation performance. For CO_2 / CH_4 mixture gas (30/70 by volume) test, the membrane (PD1 prepared by CHMA 1.0% and TMC 0.5%) showed a CO 2 permeance of 25 GPU and the best CO 2 / CH 4 selectivity of 28 at stage cut of 0.1. The high CO 2 / CH 4 separation performance of CHMA-TMC / PSf thin film composite membrane was mostly accredited to the thin film thickness and the properties of binary amino groups.