The invention discloses a remote-control step voltage alarm trolley and an alarm method thereof. The remote-control step voltage alarm trolley comprises a remote controller and a controller, and is characterized in that the controller is located on a remote control trolley body and wirelessly connected with the remote controller, the remote control trolley body is of a structure with the front-and-back length being adjustable, a front chassis is provided with an inserting slot inwards, a rear chassis is provided with an inserting rod inwards, the inserting rod is slidably inserted in the inserting slot, the inserting slot is provided with a fastener between the inserting slot and the inserting rod, the front of the front chassis is provided with an independent driving motor, either a front wheel or a rear wheel is of a metal wheel structure, the metal wheel is connected with a slip ring through a hub, the metal wheel, the hub and the slip ring are electrically connected, the slip ring is connected with an axle in an insulated manner through an insulating ring, and the slip rings are respectively connected to the input end of a step voltage alarm arranged on the remote control trolley body through elastic pieces which are slidably connected with the slip rings and fixed on the remote control trolley body. According to the invention, long-distance remote control can be realized for the trolley, detection is carried out on the periphery of broken-down equipment from far and near, and an alarm is given out when the step voltage exceeds set voltage, thereby greatly reducing occurrence of personal electric shock casualty accidents.