In order to solve the problem of poor recognition effect of the plum blossom needle of the water meter in the process of factory calibration when it rotates at a high speed close to half of the acquisition frequency, a counting method of the plum blossom needle of the water meter based on the adaptive peak picking method is proposed. Firstly, the image is preprocessed and converted into a binary image. Then, the background XOR method is used to perform XOR operations on the current frame image and the starting frame image to obtain the motion trajectory of the plum blossom needle, and the change in the proportion of white pixels is calculated during the rotation process of the plum blossom needle. Finally, the number of rotating teeth is counted through the adaptive peak picking algorithm. The experimental results show that the algorithm overcomes the interference of false wave peaks on the peak picking algorithm. Compared with traditional statistical methods, this method has a significant recognition effect on the number of rotating teeth of plum blossom needles, with an error of no more than 1%.