The importance of radial and circumferential displacement measurement for complex structural products was expounded, the limitations and shortcomings of traditional displacement measurement were introduced,a displacement measurement system based on micro-fiber probe and optical imaging technology was proposed. The test system was analyzed, designed and calculated from the structure, working principle, calibration system, displacement calculation, digital image processing and interface design in detail, further more, the innovation and technological progress of the test system were also discussed.which proved that the test system had certain reference value in similar industries.