The invention discloses a fatigue and weak state on-line test device for a high-voltage circuit breaker operation spring and relates to the technical field of high-voltage equipment test. The fatigueand weak state on-line test device for the high-voltage circuit breaker operation spring comprises an industrial camera, an LED light source, a force sensor, a data acquisition module, a test controlmodule and a spring state identification and analysis system. Spring deformation images and spring stress data are collected through the industrial camera and the force sensor respectively; the springstate identification and analysis system realizes effective identification of fatigue and weak state of the spring; and the spring state identification and analysis system adopts an NCC-SAR algorithmto identify a spring deformation target in the whole opening/ closing process, draws a characteristic point curve of spring deformation, realizes synchronous analysis of spring stress condition basedon combination of the force sensor, and makes a comparison with an experience rule database and a basic database to achieve a spring fatigue and weak state identification purpose. The algorithm has adaptivity, and spring fatigue and weak state identification correct rate is improved.