The utility model discloses a transient property detection device for a miniature circuit breaker, and the device comprises a separation mechanism, a power-on test mechanism, and an unaccepted product rejecting mechanism, wherein the separation mechanism comprises a first baffle plate. The power-on test mechanism comprises a test fixture, a jack apparatus, and a power-on mechanism. The jack device enables a product to be jacked from a conveying belt. The test fixture is used for fixing the product. The power-on mechanism is used for supplying power to the product. The unaccepted product rejecting mechanism comprises a push cylinder, a chute, and a plastic box. The plastic box is used for collecting unaccepted products, and a box made of other materials can also be used. After testing, a qualified product is conveyed to the next working procedure through the conveying belt, and an unaccepted product is pushed to the chute through the push cylinder and then conveyed to the plastic box. Compared with the prior art, the device is simple in structure, achieves the automatic production through the separation mechanism, the power-on test mechanism, the unaccepted product rejecting mechanism and a specific connection structure of the above three mechanisms, is higher in efficiency, and is of great significance for the production of circuit breakers.