Ethylene, a major intermediate in manufacture of polymers and petrochemicals, is conventionally produced by energy intensive high temperature (higher than 800^oC) steam cracking of ethane. By using a proton-conducting solid oxide cell (SOC), ethylene and pure hydrogen can be co-produced at a much lower temperature via electrochemical dehydrogenation. In this paper, we report high efficient co-production of hydrogen and ethylene on a proton-conducting Ni-BaZ_r0.1Ce_0.7Y_0.2–xYb_xO_3-δ (BZCYYb) hydrogen electrode supported SOC below 400^oC. The SOC presents high Faraday efficiency as well as an ethylene selectivity close to 100%. Our approach decreases the processing energy demand dramatically with no CO₂ emission when compared with the traditional ethane steam cracking process. The low temperature electrochemical dehydrogenation process in this study provides a promising prospective for next-generation petrochemical manufacturing, shifting the paradigm from thermal chemical practice to energy-saving and eco-friendly regime.