A chemically cross-linked ZnIn2S4/reduced graphene oxide (ZIS/rGO) composite photocatalyst was synthesized as a stable sunlight photocatalyst for the degradation of 4-nitrophenol. The experimental results revealed that although the pure ZnIn2S4 exhibited reasonable visible light photocatalytic activity toward the degradation of 4-nitrophenol, it was suffered from severe photocorrosion under sunlight irradiation. In strong contrast, the chemically cross-linked ZIS/rGO possessed not only an enhanced visible light photocatalytic activity but also a dramatically improved sunlight stability. The characterization data suggested that ZnIn2S4 nanosheet was chemically interacted with rGO sheet through Znsingle bondOsingle bondC covalent bonds, leading to a tunable band structure and enhanced photocatalytic activity. More importantly, such covalent bondings between ZnIn2S4 and rGO could improve the composite's structural stability, capable of dramatically enhancing the photocorrosion resistance under sunlight irradiation. The findings of this work would provide a new means for design of visible light active and sunlight stable photocatalysts for environmental remediation applications.