The invention relates to a folding type plate anchor and an application method thereof. The folding type plate anchor is characterized by comprising two anchor plate bodies, a triangular frame and a plurality of sets of supporting rods, wherein the triangular frame is located between the two anchor plate bodies and formed by sequentially hinging three connecting beams in an end-to-end manner, and the supporting rods are used for connecting the triangular frame and the two anchor plate bodies; each anchor plate body is in a trapezoid shape, and all the sets of supporting rods are arranged on one of the connecting beams of the triangular frame at intervals; and each set of supporting rods comprise the two supporting rods, one end of each supporting rod is rotationally connected with the corresponding connecting beam, the other end of each supporting rod is fixedly connected to the inner side of one anchor plate body, and the common end of the other two connecting beams located on the triangular frame is fixedly connected with one end of a mooring anchor chain.