The utility model relates to a locking ring that pressure vessel and this pressure vessel used, pressure vessel includes the cover, the opening is personally experienced sth. Part of the body towards the jar on the right side, the cover edge of turning up, external the turning over of jar is followed and the locking ring, it connects the tooth to be equipped with the cover on the cover turns up and follows, jar external turning over is equipped with the tank connection tooth on along, the axial interval is equipped with a left side on the locking ring internal face, right side enstrophe is followed, it connects the tooth to be equipped with a left side on the enstrophe edge of a left side, it connects the tooth to be equipped with the right side on the enstrophe edge of the right side, jar body recess form to supply a left side to connect a left side that the tooth passed from the dextrad left side passageway of stepping down, right side enstrophe supplies the cover to connect tooth from a dextrad left side entering left side along recess formation, the right side right side of enstrophe between along the passageway of stepping down, the locking ring can make a left side connect gear position in the left side of tank connection tooth when rotating, the right side is connected gear position and is cooperated with realization axial block in the right side of cover connection tooth, only need rotate the locking ring that weight is lighter during dismouting simultaneously can, weight great the jar body or cover need not rotate yet, the efficiency of pressure vessel's dismouting is greatly improved.