The invention discloses a general aero-engine external pipeline space size detection and setting device, which comprises a magnetic platform, a positioning bottom plate, a sliding frame, a pipe body positioning assembly, a joint positioning assembly A, a joint positioning assembly B, an angle adjusting assembly and a workpiece; the positioning bottom plate is adsorbed on the magnetic platform through magnetic force, and the lower part of the sliding frame is connected with the positioning bottom plate; a sliding groove is formed in the sliding frame, the connector positioning assembly A and the connector positioning assembly B are connected with the two ends of a workpiece respectively, and the angle adjusting assembly is arranged on the outer side of the middle of the workpiece in a sleeving mode. The general aero-engine external pipeline space size detection and setting device has the design advantages that the device is high in bending compatibility for workpieces with different diameter specifications and different bending angles, simple in device mechanism, convenient and accurate in measurement method, high in universality, simple in design structure, stable, safe, reliable, low in manufacturing cost, easy to manufacture and reusable; and in the using process, convenience and rapidness are achieved, and operability is high. The device can be popularized and applied to various machining fields.