Abstract: The array shape towed under water will generate a certain distortion if the movement of towing device changes. And, the slower the towing speed, the greater the distortion magnitude, obviously the distortion affects the detection performance. To improve the detection performance of the towed array, how the array shape changes in different towing states needs to be researched. This paper introduces the research results based on these demands, and proposes using the stochastic resonance (SR) technique and Doppler shift character to build a shape estimation system of towed array. This system can provide precise estimates of the array shape in real time to meet the needs of shape estimation technique for towed array sonar.