In order to solve the problem of direct survey of cable well caused by water, a direct survey technique for the internal state of cable wells using sonar imaging based on the remotely operated vehicle（ROV） platforms is proposed. The terminal sliding mode control is used as the closed loop control of ROV. By using the particle swarm optimization algorithm to optimize the parameters and eliminate the influence of the disturbance observer on the uncertainty, the accurate control of the ROV 's walking position in the cable well is achieved, and the sonar imaging technology is used to realize the direct observation of the cable laying state in the cable well. The test results show that the improved sliding mode control model can realize the accurate control of the ROV's walking position, with the control accuracy of 0.1 m. The sonar imaging sensor can realize the measurement of the cable distribution status and cable size in the cable well, with the measurement accuracy better than 5%. The proposed sonar survey technology for cable wells based on ROVs can directly survey the internal state of cable wells, greatly reducing the survey work of operators and having high practical application value in production.