Both pristine metal-organic frameworks (MOFs) and graphitic carbon nitride (g-C3N4) displayed outstanding photocatalytic performances toward H-2 production, CO2 reduction, Cr(VI) reduction and organic pollutants degradation. To further enhance their photocatalytic performances under visible light or sunlight irradiation, MOFs and g-C3N4 were combined to construct g-C3N4/MOF heterojunctions with the purpose of overcoming their individual disadvantages like fast recombination of pohotogenerated electron-hole pairs. The fabrication methods, characterizations, photocatalytic performances and the corresponding mechanism of some typical g-C3N4/MOF composites were highlighted. Also, the prospective and challenges of this research field were declared.