In order to measure tube busbar deflection and ensure that it works effectively, a new contactless measurement method is proposed. First, a computer binocular stereovision measurement system is established, and intrinsic and extrinsic parameters of cameras are developed by shooting a target. Next, according to the wavelet packet, mathematical morphology and binarization processing are used to denoise original images. Finally, the measurement point is extracted from binarization processing images, the pixel co-ordinate is recovered, and the deflection of the tube busbar is calculated. This method is applied in tube busbar real-time deflection monitoring in a 500kV transformer substation, and the deflection curve is obtained. The results show that this method can work effectively.