Abstract: For the problem that it-s difficult to measure the blade tip clearance of turbine engines and its low accuracy, a high-precision measurement for blade tip clearance in the assembly process was proposed by utilizing image measurement, through using the defined calibration, an improved edge detection, the Hough transform and image super-resolution restoration technology, as well as operating the motion control mechanism, the industrial CCD camera and the open source computer vision library, an unique image measurement system was designed to achieve the high-accuracy and non-contact measurement of blade tip clearance. The experimental results show that the measurement accuracy reaches 15 m.Compared with other tip clearance measurement and image measurement system, this method not only improves accuracy, but also has a good portablility, low cost and stronger applicability.