The present disclosure provides a device and a method for detecting a level degree of an OHCV. The device may include a laser beam transmission unit, at least one baffle, a laser beam reception unit, and a controller. The laser beam transmission unit, the baffle and the laser beam reception unit may be sequentially arranged at an identical horizontal level inside the OHCV. The at least one baffle may be provided with a via-hole. The laser beam transmission unit may be configured to generate a laser beam through the via-hole and toward the laser beam reception unit. The laser beam reception unit may be configured to receive the laser beam and transmit information about the received laser beam to the controller. The controller may be configured to monitor the real-time information about the laser beam. According to the present disclosure, it is able to conveniently detect the level degree of the OHCV, effectively reduce the workload of an inspector and enable the inspector to inspect the OHCV without entering an interior of the OHCV, thereby to prevent the normal operation and the cleanliness of the OHCV from being adversely affected.