The invention discloses a shape correcting device of a flame tube shell of a gas turbine. The shape correcting device of the flame tube shell of the gas turbine aims to solve the problems that according to the prior art, the shape correcting process of the flame tube shell is complicated, working efficiency is low, shape correcting needs to be carried out manually, shape correcting accuracy is too low to meet requirements of products, a large number of manpower and material resources are consumed, and cost is high. The shape correcting device of the flame tube shell of the gas turbine comprises a base, a pressing plate, an ejector block, a locking piece, a set of molded line expansion block, four lifting pins and four springs, wherein the four springs are arranged on the set of molded line expansion block, the four lifting pins are evenly arranged on the base, the set of molded line expansion block is arranged on the upper surface of the base, the pressing plate is arranged on the set of molded line expansion block, the locking piece penetrates thought the base and then is arranged on the set of molded line expansion block, and the ejector block is arranged on the locking piece. The device is used for shape correcting of the flame tube shell of the gas turbine.