To address the problem wherein the traditional measurement method based on the fixed length segmentation of the cylindrical point cloud method cannot efficiently and accurately measure the bending radius of a bent tube, an adaptive cylindrical point cloud segmentation based on the bending segmentation of the bent pipe measurement method is proposed. First, the main direction of the bend point cloud is calculated based on the normal vector information of the bend. Next, the main direction of the bend point cloud is globally oriented by the diffusion method. Then, based on information related to the main direction and with the aid of the regional growth clustering method, adaptive segmentation of the bend point cloud is realized. For each segment of the cylindrical point cloud derived from the segmentation, the axes of the bends are extracted based on cylindrical fitting by the Levenberg-Marquardt (L-M) method. Finally, the bending segment nodes are obtained according to the critical curvature of the axis nodes, and a bending radius calculation is performed. Experimental results show that, for the bent section of a bent tube, this method has a measurement accuracy of no less than 0.18 mm. The proposed method is simple and efficient and requires very little manual operation. The method is proven to meet aerospace field requirements for bent tube measurements.