Methane conversion into ethanol and associated derivates under mild reaction conditions is of great significance, yet remains a challenge to date. Herein, we report efficient photocatalytic methane conversion into C2-hydrocarbons by using CO2 as a soft oxidant over a series of Zn-doped g-C3N4 composites. The results indicate that Zn atoms enter the lattice of g-C3N4 and are chemically coordinated therein in the form of ZnN bonds. The integration of Zn, on one hand, could increase the specific surface area thus surface alkaline sites, and broaden the light response ability as well, promoting the dehydrogenation of methane into methyl. One the other hand, it is found that the ZnN bonds could serve as electron channels, accelerating the charge separation inside g-C3N4 and enabling rapid electron transfer from g-C3N4 to surface photodeposited Ru cocatalyst. This unique behavior changes the photocatalytic pathway and promotes the formation of CH3CHO and CH3CH2OH, as demonstrated by our in-situ infrared spectroscopy. Our photocatalytic tests indicate that the 0.5% Ru/Zn-g-C3N4-1/20 composite possesses the best activity, with the yields of CO, CH3CHO, and CH3CH2OH up to 865.25, 330.38, and 1442.88 μmol/g in 3 h, respectively. A proposed reaction mechanism based on the experimental results and above characterizations was finally deliberated.