Abstract: Composite material insulated crossarms have the advantages of light weight, high strength, excellent insulation performance, and strong corrosion resistance. They are gradually replacing traditional metal crossarms, greatly improving the stability and safety of distribution network operation. This article delves into the working principle, design principles, material properties, and durability of composite insulated crossarms, listing commonly used glass fiber reinforced plastics, carbon fiber reinforced plastics, etc., and conducting in-depth analysis and comparison of key properties such as mechanical strength, corrosion resistance, and weather resistance of the materials. The excellent performance of composite insulated crossarms is verified through durability evaluation.