The invention discloses a switch cabinet as well as a breaker trolley position detection device and an application method thereof. The breaker trolley position detection device of the switch cabinet comprises a reflector, a laser sensor and a control module, the reflector is mounted on a contact arm of a switch cabinet breaker trolley, the laser sensor is a rotatable laser transceiver with rotating and rotation angle detection functions; the switch cabinet comprises the breaker trolley position detection device; and the application method comprises the steps of comparing a rotation angle of the laser sensor with a calibration angle and determining whether the trolley is pushed in place. The switch cabinet and the breaker trolley position detection device thereof can realize breaker trolleyposition detection, and the application method can determine whether a movable contact and a static contact are contacted in place and whether pushing-in depth is qualified or not, thereby being applicable to breaker trolley position identification of a 10-35kV switch cabinet in an operation process and timely pre-warning an equipment state.