Based on the large-scale wall-pressing three-legged crawler pipeline inspection robot, our team proposed a cornering algorithm based on space constraints, that aims to better control the smooth operation of the pipeline robot in the pipeline. This algorithm is aimed at large robots that use an electric telescopic rod structure to replace the elastic structure on traditional small robots. The electric telescopic rod structure meets the large-scale weight change of the robot and provides sufficient supporting force. However, this structure also makes it difficult for the robot to automatically adapt to the change of pipe diameter and increases the difficulty of the robot’s control. In order to solve this problem and more accurately control the operation of the robot during cornering, this paper analyzes the space constraints of the robot when turning, the optimization analysis of the telescopic rod expansion and the ratio of the speed of each crawler, obtaining a stable turning algorithm for pipeline robots. The algorithm guarantees that the robot can provide sufficient support in the bend pipeline, and that it has good stability and mobility.