A grass protection mat and a mat assembly having the same are provided. The grass protection mat of the invention includes a body made of polygonal portions, pillars protruded upward from the body, buffer wings protruded upward from the body between the pillars for distributing weights, an outer frame at the periphery of the body, lug members protruded from lower parts of the body and the outer frame. The mat also includes slide-type hooking means laterally protruded for connection of the mats, an opening formed at the inner surface of the outer frame. The mat assembly includes various forms of mat fastening members for connecting the grass protection mats. The invention facilitates connection of the mats and enhances assemblability of the mat assembly, effectively preventing sinking of the mats into the ground, thereby maintaining protection of grass.