The utility model relates to a reinforcement plate for a pressure container and a liquefied gas storage and transportation tank comprising the reinforcement plate, which can reduce the weight of the liquefied gas storage and transportation tank and the manufacturing cost. A shell of the reinforcement plate is shaped like a corrugated plate, i.e. the section of the reinforcement plate has any one of the shapes of concave tile, arc, semicircle, semiellipse, trapezoid and polygon, so that a bending moment of the shell, caused by the inner pressure of the reinforcement plate, is converted into circumferential stress (when drapes of the shell are shaped like the concave tile, the semicircle and the semiellipse), and the bending stress can be greatly reduced (when the drapes of the shell are shaped like the trapezoid and the polygon); furthermore, the height of a main material is increased according to the height of an arc on the shell compared with that of a general reinforcement plate; meanwhile, the shell is a flat plate, the stress distribution is more uniform than that of the shell of the general reinforcement plate with a shear lag phenomenon; therefore, the hardness of the shell and the main material is improved, so that the arrangement intervals of the main material and a reinforcement beam can be increased in the comparison with those of the general reinforcement plate, so that the arrangement number of the main material and the reinforcement beam is reduced; moreover, bending of a plate on the shell is avoided, and the hardness of the shell is enhanced, so that the manufacturing cost of the liquefied gas storage and transportation tank is lowered, and the efficiency of the reinforcement plate serving as a structural component can be improved.