The introduction of metal complex units makes it possible to expand the functional applications of metal hydrogen-bonded organic frameworks (M-HOFs). An M-HOFs-templated strategy was developed to construct ultra-fine ZnCdS/ZnS heterojunction with high-porosity for efficient photocatalytic hydrogen production. Due to the weak and feasible hydrogen-bonding interactions, the nonmetallic units on HOFs can be quickly replaced by S2− in aqueous solution and derived into porous sulfides without pyrolysis process. Surprisingly, the surface area of ZnCdS/ZnS heterojunction was up to 320 m2 g−1. The ultra-fine heterojunction with high porosity offered more surface reaction sites and shortened carrier transport distance, improving separation efficiency of photogenerated electrons and holes. The size and structure-dependent properties of ZnCdS/ZnS heterojunction exhibited excellent photocatalytic hydrogen evolution rate, which was 1.68 mmol h−1 without cocatalyst. This study provides a novel strategy for constructing ultra-fine heterojunction with high porosity and high surface area to achieve efficient H2 evolution.