Abstract: A non-contact displacement test method is proposed based on the principle of optimal circle fitting, and the relevant object-oriented visualization software is developed. The proposed method is verified by the shaking table tests. The verification shows that the independently-developed non-contact displacement test method has good performance in circlic detections and displacement tests. The precision achieves sub pixel accuracy. The horizontal displacement of the shaking table measured by the non-contact displacement test method is compared with that by the strain type displacement meter. The comparison shows that the similarity degree of displacement distribution patterns between the above two methods is 0.98. The packaged technique efficiently solves the problem of displacement tests under inconvenient conditions to set up sensors and test range restricted by the traditional displacement test methods, and it may avoid the interference to the measured objects.