The material used for manufacturing low-voltage cable branch box box is a kind of resin matrix composite material. The main components of the box are ABS engineering plastic, polycarbonate transparent PC material, DMC, SMC four kinds of materials injection molding and pressing. This kind of composite material is composed of two parts: matrix polyester resin; reinforced material (PC, SMC for short), so it is also called transparent PC material and fiber reinforced polyester material. Transparent PC material and fiber reinforced unsaturated polyester is a kind of composite material based on unsaturated polyester resin. The two materials are insoluble, flame retardant and recyclable, while the latter has the disadvantages of non melting and non recycling. Its physical structure is three-dimensional network structure. These four materials have become high-performance engineering materials through functional filler modification and special fiber reinforcement. In developed countries such as Europe and the United States, this material has been widely used in the electrical field as early as several decades ago.