The invention discloses a method for analyzing the positioning state of a large-forging plastic forming blank on a forging die. Firstly, a five-element four-level orthogonal analysis table is built according to deviation indexes delta X, delta Y, theta, alpha and beta of the instantaneous initial position, at the moment when the blank is released to a forging-die lower die from an operating machine, of the blank relative to an ideal initial position in different directions; secondly, the process that the blank is released from different initial positions and freely drops into a lower die cavity freely under the action of gravity is analyzed through multi-body dynamics analysis software to obtain the position and posture of the blank at moment when the blank drops into the lower die cavity and is balanced, and the deviation amount of the position and posture of the blank relative to an ideal malleable-state position determined according to a forging technology is calculated; a deviation index having the largest influence on the deviation of the blank with the position and posture from the ideal position after the blank falls into the lower die is obtained according to the range analysis method and serves as a blank initial position parameter which should be strictly controlled preferentially. The method can provide reference for positioning of the large blank on the forging die, so that time spent in auxiliary operation before forging is shortened.