A system comprising: - a bottle blow moulding machine, - a quick die changing mechanism, including: - a die shell arranged on a bottle blowing machine, - a die, - a first connecting hole is formed in the die shell; - a second connecting hole is formed in the die, - a connecting piece connects the die shell and the said die through the first and second connecting holes, wherein, the connecting piece comprises a first part and a second part, the die shell is connected to the first part fixedly, the die is connected to the second part in a removable mode, and the maximum width of the second part is less than or equal to the second connecting hole aperture, - a boss is formed at the wall of the second connection hole towards its center, the outermost edge of one side of the second part of the connecting piece against the boss, contacts with the boss or closer to the axis of the second part, compared to the boss, - a locking piece connected to the outer end of the second part rotates around a rotation axis, the locking piece has two working statuses at least, wherein - at the first working status, the locking piece blocks the boss at the outside of the boss, so that the die is positioned relative to the die shell; and - at the second working status, the locking piece keeps away from the boss, so that the die can move along the direction of the axis of the second part of the connecting piece to depart from the die shell, the system being characterized in that: - the vertical section of the locking piece is an arc surface consisting of a circular arc and a line segment that connects two endpoints of the circular arc, the vertical section of the locking piece consisting of line segment is a matching surface, whose shape and position matched with the boss, - when the locking piece at the second working status, projections of the matching surface and the surface of the boss being towards the connecting piece on a plane that is perpendicular to the axis of the second part of the connecting piece, contact each other, or gap exists between projections; - when the locking piece at the first working status, projections of the locking piece and the boss on a plane that is perpendicular to the axis of the second part of the connecting piece partially overlap at least. - a bottle blow moulding machine, - a quick die changing mechanism, including: - a die shell arranged on a bottle blowing machine, - a die, - a first connecting hole is formed in the die shell; - a second connecting hole is formed in the die, - a connecting piece connects the die shell and the said die through the first and second connecting holes, wherein, the connecting piece comprises a first part and a second part, the die shell is connected to the first part fixedly, the die is connected to the second part in a removable mode, and the maximum width of the second part is less than or equal to the second connecting hole aperture, - a boss is formed at the wall of the second connection hole towards its center, the outermost edge of one side of the second part of the connecting piece against the boss, contacts with the boss or closer to the axis of the second part, compared to the boss, - a locking piece connected to the outer end of the second part rotates around a rotation axis, the locking piece has two working statuses at least, wherein - at the first working status, the locking piece blocks the boss at the outside of the boss, so that the die is positioned relative to the die shell; and - at the second working status, the locking piece keeps away from the boss, so that the die can move along the direction of the axis of the second part of the connecting piece to depart from the die shell, - the vertical section of the locking piece is an arc surface consisting of a circular arc and a line segment that connects two endpoints of the circular arc, the vertical section of the locking piece consisting of line segment is a matching surface, whose shape and position matched with the boss, - when the locking piece at the second working status, projections of the matching surface and the surface of the boss being towards the connecting piece on a plane that is perpendicular to the axis of the second part of the connecting piece, contact each other, or gap exists between projections; - when the locking piece at the first working status, projections of the locking piece and the boss on a plane that is perpendicular to the axis of the second part of the connecting piece partially overlap at least.