Plywood can be structured, adhesive properties, surface processing, treatment methods, shape, use to classify, commonly used is an ordinary plywood. Plywood commonly known as three plywood, five plywood, nine PCT board, twelve PCT board. Its thickness specifications are 2.7,3,3.5,4,5,5.5,6,7,8 mm, commonly used specifications are 3,3.5,4 mm. Plywood boards can be full, and also allow splicing. The veneer of the symmetrical layer on both sides of the center layer shall be the same thickness, the same tree species or similar tree species, the same processing method (peeling or slicing), the same texture direction. Adjacent two-layer veneer grain direction should be the same.