The feasibility of perlite particles used in poly(ε-caprolactone) (PCL)/poly(lactic acid) (PLA) composite films by melt blending is explored to improve their mechanical property and analyze their antibacterial effect. The effect of perlite content on the mechanical, thermal, hydrophilic, and antibacterial properties of composite films is investigated. Results show that incorporation of 10 wt% perlite in PCL/PLA film improves the tensile strength and hydrophilicity by 1.2 times and 25 %, respectively. After perlite addition, the melting crystallization and glass transition temperature of PCL/PLA film are improved. The presence of perlite also confers antibacterial benefits to the composite film. PLA-based materials are used in the fields of medical materials and food packaging, and their ability to degrade in seawater has been a long-standing goal. In this study, the addition of PCL and perlite not only increases various properties and antibacterial effects, but the blending of inorganic materials and organic materials can destroy the link strength of polymer chain segments of organic materials and help them degrade in seawater. The prepared composite film features broad prospects for the development and application of various fields, such as food packaging and medical materials, reduce white pollution in the ocean.