In order to understand the deformation of sluice gate in time and ensure the safe operation of water conservancy project,the transient detection method of horizontal displacement of sluice gate based on three-dimensional imaging technology is studied.The three-dimensional imaging technology based on optical projection tomography is used to collect the sluice image.Through the transient detection method of sluice horizontal displacement based on image processing technology,combined with four image processing technologies:spot recognition,image filtering,edge detection and circle center fitting,a spot differential circle fitting center positioning algorithm is proposed to determine the spot center of the collected image,taking the center position of the cross target as the reference point,the offset of the spot center relative to the reference point is measured to realize the transient detection of the horizontal displacement of the sluice.The experiment results show that the integrity of the facula curve is high,and the position of the facula center of each image is more accurate.The transient detection results of each detection point are basically consistent with the actual results obtained by the monitoring extensometer.The horizontal displacement of the sluice gate changes periodically every year and is inversely proportional to the temperature.