The invention relates to a circuit breaker, a spring actuating mechanism and a latch assembly thereof, A spring actuating mechanism includes a tab and a latch assembly, The latch assembly includes a base and a latch rotatably mounted on the base, the latch having a stop position for stopping the earpiece and a release position for releasing the earpiece on a controlled reciprocating swing stroke,and at least two electromagnets arranged in parallel on the base and independently drivable from the stop position to the release position for swinging the latch from the stop position. The number ofelectromagnets that drive the latch to swing from the stop position to the open position is at least two, and each electromagnet is arranged in parallel with each other and can drive the latch individually. In the present invention, the electromagnets can be individually driven without affecting each other, as compared with the prior art arrangement of a plurality of electromagnets in series. Evenif one of the electromagnets fails, the rest of the electromagnets can still drive the latch to swing, and the whole switching process of the spring-operated mechanism is not affected.