We reported a strategy of carbon‐negative H2 production in which CO2 capture was coupled with H2 evolution at ambient temperature and pressure. For this purpose, carbonate‐type CuxMgyFez layered double hydroxide (LDH) was preciously constructed, and then a photocatalysis reaction of interlayer CO32− reduction with glycerol oxidation was performed as driving force to induce the electron storage on LDH layers. With the participation of pre‐stored electrons, CO2 was captured to recover interlayer CO32− in presence of H2O, accompanied with equivalent H2 production. During photocatalysis reaction, Cu0.6Mg1.4Fe1 exhibited a decent CO evolution amount of 1.63 mmol g−1 and dihydroxyacetone yield of 3.81 mmol g−1. In carbon‐negative H2 production process, it showed an exciting CO2 capture quantity of 1.61 mmol g−1 and H2 yield of 1.44 mmol g−1. Besides, this system possessed stable operation capability under simulated flu gas condition with negligible performance loss, exhibiting application prospect.