Abstract:PGS(PEI)/CaIn2S4 composites was prepared by a one-pot hydrothermal method using polyethyleneimine (PEI) modified palygorskite (PGS(PEI)) and CaIn2S4 precursor as raw materials. The physicochemical properties of PGS(PEI)/CaIn2S4 composites were characterized by means of XRD, SEM, N2 adsorption-desorption, UV-Vis DRS and PL. The growth mechanism of the composite was described and the feasibility of photocatalytic degradation of various dyes was tested. PGS(PEI) is embedded in flower-like nano-CaIn2S4.The maximum specific surface area, pore volume and pore diameter of PGS(PEI)/CaIn2S4 (modified PGS mass ratio of 60%) are 138.6 m2/g, 0.49 cm3/g and 14.20 nm, respectively. The photogenerated carrier separation rate of composite increases attributing to the built-in electric field between PGS(PEI) and CaIn2S4 and the photoelectron transformation by PEI. Thephotocatalytic activity of 60% PGS(PEI)/CaIn2S4 for methylic orange (MO) degradation is higher than CaIn2S4 under the visible light. The degradation rate of MO is 96.9% for 60 min. The superoxide free radicals (.O2-) play an important role in the photodegradation process.