Fiber optic displacement sensor is introduced to measure the trip of the circuit breaker’s moving contact against deficiencies of the displacement sensors used by previous online monitoring system, which leads to high-accuracy and low interference. An analysis method based on Hilbert-Huang Transform to extract moment-close point is put forward. The intrinsic mode function (IMF) component which contains speed signal partial characteristic is extracted by empirical mode decomposition(EMD). The IMF component is selected by the variance contribution rate according to the speed characteristic of the moment-close point. Thus the selected IMF component can be analyzed by instantaneous amplitude after Hilbert transform, whose feature point is the moment-close point of the circuit breaker. The experiment results shows that the analysis method could extract the moment-close point effectively and accurately, providing credible information for the fault diagnosis of circuit breaker.