The present invention discloses a tunnel surrounding rock deformation monitoring device and method. The device comprises a measurement support, a leveling pedestal and an assistant position device. The measurement support is vertically arranged on the leveling pedestal through a channel, is able to horizontally move along the channel and is provided with a laser range finder with adjustable height and an observation target, and the assistant position device includes a support bar vertically arranged and a laser locator fixed on the support bar. The tunnel surrounding rock deformation monitoring device and method are configured to employ a laser locator to perform spatial orientation and employ a laser range finder with an adjustable height and a channel adjusting the horizontal position of the measurement support so as to realize that the origins of each measurement are all located at the same straight line in a three-dimensional space and conveniently and rapidly determine the whole deformation characteristics of the tunnel surrounding rock.