The invention provides a screen cabinet replacement device, which comprises a walking base, two supports, a sliding frame and a control bench. The two supports are arranged on the walking base; a space for allowing a screen cabinet to pass is formed between the two supports; the two ends of the sliding frame are connected to the side surfaces of the two supports respectively; the sliding frame isprovided with a clamping plate extending in the sliding direction of the sliding frame; the clamping plate is provided with a clamping groove for clamping the screen cabinet; the clamping plate is also connected with a first lifting assembly for driving the clamping plate up and down; and the control bench is arranged at one side of the walking base or one support, and electrically connected withthe first lifting assembly. The invention also provides a screen cabinet replacement method. According to the screen cabinet replacement device and method, replacement can be operated by a single person, thereby reducing the number of workers involved in operation and effectively reducing labor cost. Meanwhile, the screen cabinet replacement device also occupies a small space and can still be operated in a narrow passage.