The development of novel hybrid photocatalysts with high efficiency and durability for photocatalytic degradation and hydrogen production is highly desired, but still remains a great challenge currently. In this work, novel hierarchical composites consisting of petal-like Zn3In2S6 nanosheets and varying amounts of fluorine doped polymeric carbon nitride (FCN) were successfully prepared as photocatalysts for the photocatalytic degradation of methyl orange and H-2 evolution under visible light irradiation. The incorporation of FCN into Zn3In2S6 nanosheets significantly enhanced the photocatalytic activity for H-2 evolution (reduction) and degradation of methyl orange (oxidation). And the best-performing Zn3In2S6/FCN composite (i.e., ZF3) exhibited enhanced visible-light-driven photocatalytic methyl orange degradation efficiency of about 7.36 and 5.35 times higher than those of pure FCN and Zn3In2S6, respectively. Trapping experiments combined with electron spin resonance spectroscopy indicated that the active radicals (center dot O-2(-) and center dot OH) and oxidizing h(+) were responsible for the photocatalytic reaction. Meanwhile, the cumulative H2 evolution quantity by ZF3 sample via photocatalytic H-2 evolution from water splitting under 5 h of light irradiation reached 2553.9 junol.g(-1), which was 3.66 times higher than that of Zn3In2S6 (698.2 pmol.g(-1)). Cyclic tests demonstrated the stability of the ZF3 composite over five cycles of repeated use. These excellent performances were found to be attributable to the remarkable charge carrier separation between FCN and Zn3In2S6, with the aid of interfacial heterojunction structures. Based on the above results, the possible photocatalytic reaction mechanisms of ZF3 composite in both pollutant degradation and H-2 evolution from water splitting were also proposed. This study provides new insights into the preparation of highly-efficient hierarchical composite photocatalysts, which are promising for implementation in wideranging environmental applications.