The invention relates to a surface flame retarded wood plastic composite plate and a method for preparing the same, which relates to a composite material, an environment-friendly material and a method for preparing the same. The composite material is applicable to making the following products: floor boards, shelf boards, and the like for means of transportation such as automobiles, planes, and the like in the field of transportation; road slabs, fences, wallboards, aisle guard bars, and the like in the field of construction; and outdoor desks and chairs, office partition boards, storage boxes, flower boxes, adjustable shelves, beach chairs, and the like in the furniture industry. The surface flame retarded wood plastic composite plate consists of two layers of crystal whisker modified plastic layers and plant fiber reinforced plastic layers, wherein the plant fiber reinforced plastic layers are arranged between the two layers of the crystal whisker modified plastic layers through die stamping. The crystal whisker modified plastic layers are made from modified basic magnesium sulfate whiskers, plastic particles, and the like through mixed calendering. The plant fiber reinforced plastic layers are made from plastic particles and plant fibers through mixed calendering.