The invention relates to the field of quick-opening type pressure vessels, and aims to provide a quick-opening type pressure container sealing head position adjusting mechanism and method. The adjusting mechanism comprises sealing head rib plates, a supporting arm, a cross head, a rib plate gland, a cross head communicating rod and a cross head communicating rod gland, wherein the sealing head ribplates are vertically welded to the surface of a sealing head, the tail section of the supporting arm is arranged between the sealing head rib plates, the cross head is arranged in the tail section of the supporting arm and is sleeved on the middle section of the cross head communicating rod, and the rib plate gland and the end part of the cross head are sleeved and matched with each other. The adjusting mechanism and method have the advantages that the structure is simple, the operation is convenient, by means of gland screws, gland nuts, a large gland locking nut and the cross head communicating rod gland on the mechanism, the relative positions of the supporting arm and the sealing head can be adjusted, and the sealing head and a main body can be guaranteed to be located at the centered positions; in addition, good economic benefits are achieved; and by means of the mechanism, after the position of the sealing head is deviated, the sealing head and the supporting arm do not need tobe replaced again, the sealing head can be continuously used only through proper adjustment, and therefore materials are saved, and the cost is lowered.