The regulation of gas sorption via simple pore modification is crucial to molecular recognition and chemical separation. Herein, a rational pore surface electrostatic modulation in synthetic one dimensioned (1-D) channel is demonstrated to boost ethane/ethylene (C₂H₆/C₂H₄) selectivity for one-step extraction of C₂H₄ from C₂H₆/C₂H₄ mixtures. Through the precise modulation of the surface charge arrangement with negatively charged moieties in the 1-D channel of a metal–organic framework (MOF), enhanced C₂H₆–host framework and decreased C₂H₄–host framework electrostatic interactions were obtained, which resulted in an obvious improvement in adsorption selectivity. Furthermore, the breakthrough separation performance rendered the obtained MOF an efficient adsorbent for C₂H₄ purification from C₂H₆/C₂H₄ mixture. The combined detail theoretical studies prove that the gas sorption selectivity is remarkably sensitive to framework electrostatic change even in the case of pore surface modification at the atomic level. These results are of fundamental importance to the design of porous materials for challenging separation tasks.