A method for monitoring a circuit breaker, including: (a) obtaining a first data set representing force applied to a fixed point of an element of an actuating mechanism of the circuit breaker in present operation cycle; obtaining a second data set representing force applied to the fixed point in a plurality of operation cycles from a history profile when the circuit breaker is operated normally; and extracting the normal operating condition related parameters for each of the operation cycles from the force represented by the second data set; (b) judging a health condition of the circuit breaker in consideration of normal operating condition related parameters of the element according to the history profile when the circuit breaker is operated normally and current operating condition related parameters of the element in the present operation cycle extracted from the force represented by the first data set; (c) generating a signal indicating the health condition of the actuating mechanism of the circuit breaker; characterized in that, in the step (b): the second data set is divided into two groups respectively corresponding to a first number and a second number of the plurality of operation cycles from the history profile; in terms of the operating condition related parameter, identifying historical dissimilarity involving the respective one of the second number of the operation cycles and the first number of the operation cycles; in terms of the operating condition related parameter, identifying current dissimilarity involving the current operation cycle and the first number of the operation cycles; and the judgement of the health condition of the circuit breaker is based on a comparison of the historical dissimilarity and the current dissimilarity. (a) obtaining a first data set representing force applied to a fixed point of an element of an actuating mechanism of the circuit breaker in present operation cycle; obtaining a second data set representing force applied to the fixed point in a plurality of operation cycles from a history profile when the circuit breaker is operated normally; and extracting the normal operating condition related parameters for each of the operation cycles from the force represented by the second data set; obtaining a second data set representing force applied to the fixed point in a plurality of operation cycles from a history profile when the circuit breaker is operated normally; and extracting the normal operating condition related parameters for each of the operation cycles from the force represented by the second data set; (b) judging a health condition of the circuit breaker in consideration of normal operating condition related parameters of the element according to the history profile when the circuit breaker is operated normally and current operating condition related parameters of the element in the present operation cycle extracted from the force represented by the first data set; (c) generating a signal indicating the health condition of the actuating mechanism of the circuit breaker; the second data set is divided into two groups respectively corresponding to a first number and a second number of the plurality of operation cycles from the history profile; in terms of the operating condition related parameter, identifying historical dissimilarity involving the respective one of the second number of the operation cycles and the first number of the operation cycles; in terms of the operating condition related parameter, identifying current dissimilarity involving the current operation cycle and the first number of the operation cycles; and the judgement of the health condition of the circuit breaker is based on a comparison of the historical dissimilarity and the current dissimilarity.