A pipe fitting crimping device, comprising an outer positioning frame (1). Two or more arc-shaped extrusion modules (a) distributed in a circular array at intervals are provided in the outer positioning frame. All the arc-shaped extrusion modules surround and form a crimping space (k) allowing for the insertion of pipe fittings. All the arc-shaped extrusion modules are mounted to an inner movable elastic scaling surrounding frame (b) located in the outer positioning frame to allow for the scaling of the crimping space formed by all the arc-shaped extrusion modules. A linear propelling mechanism (c) for driving the inner movable elastic scaling surrounding frame to scale in a front-rear direction so as to drive the crimping space to scale is provided on the outer positioning frame. Therefore, the use is more flexible.