Abstract: The mechanical properties of Z-pin reinforced composite laminates under hygrothermal conditions were studied.Considering the effects of temperature, humidity and microstructure changes caused by pin insertion on the elastic properties, a constitutive model of Z-pin reinforced composite laminates in hygrothermal conditions was established.The damage and failure of Z-pin reinforced composite laminates under hygrothermal conditions was simulated by using finite element, and the analysis results were compared with the experimental results in the literatures.The results show that the simulation results are in good agreement with the experimentalresults in the literatures.The strength of Z-pin reinforced composites decreases with the increase of temperature.The increase of moisture absorption rate reduces the strength of Z-pin reinforced laminates, and the compressive strength is more affected than the tensile strength with increase of moisture absorption rate and temperature.