Abstract: In view of that disconnections in switch-on control circuit persistently exist and can’t be effectively monitored during normal operation of circuit breakers, and based on the cause analysis of the failed switch-on accident of circuit breakers, The paper proposes fixing delayed auxiliary contacts for control circuit to realize monitoring of circuit breakers under all operating conditions, and studies corresponding monitoring scheme for breaker control circuit, and finally proves the feasibility of such a design concept by simulation analysis.