The cost-effective and durable electrocatalysts for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is vital to overall water splitting and regenerative metal-air batteries. Herein, we presented a simple metal organic framework (MOF)-based approach for facile fabrication of noble-metal-free trifunctional heterostructure electrocatalysts. Different from traditional MOF-derived composite materials, Mo2C nanosheets are vertically aligned on the surface of cobalt-embedded nitrogen-doped carbon polyhedron (Mo2C/Co@NC). Benefiting from the reciprocally permeated structure and strong interfacial coupling effects between Mo2C nanosheets and Co@NC polyhedron, the intrinsic activities and the accessible active sites toward HER, OER and ORR are significantly improved, which endows Mo2C/Co@NC with high electrocatalytic activity and durability as a trifunctional electrocatalyst. Notably, Mo2C/Co@NC-based Zn-air battery could efficiently power the electrochemical water splitting using Mo2C/Co@NC as the electrodes. This work provides one heterostructural protocol to construct new types of noble-metal-free trifunctional electrocatalysts for boosting water splitting and zinc-air batteries.