The invention belongs to the technical field of nuclear fuel assemblies, and concretely relates to a square double-sided cooling annular fuel assembly. The invention aims at developing and designing the square double-sided cooling annular fuel assembly in order to solve the problems of easy fission, gas release amount increase, aggravated cladding corrosion and hydrogen absorption, fuel pellet swelling and accelerated growth of fuel elements and assemblies in the use process of existing rod fuel assemblies. The square double-sided cooling annular fuel assembly is characterized in that the square double-sided cooling annular fuel assembly comprises an upper tube seat, fuel rods, positioning grids, a lower tube seat, guiding tubes and an instrument tube; the fuel rod, the guiding tubes and the instrument tube are inserted in the positioning grids; the quantity of the positioning grids is more than one, and the positioning grids are sequentially arranged axially; the upper ends of the guiding tubes and the instrument tube are fixedly connected with the upper tube seat, and the lower ends are fixedly connected with the lower tube seat; and the lower ends of the fuel rods are suspendedand are not in contact with the lower tube seat, so the fuel rods expand up and down when irradiation growth of the fuel rods occurs. The square double-sided cooling annular fuel assembly significantly improves the economical property and safety of nuclear power and extends the service life of nuclear power plants.