The invention provides a rope ladder device for maintenance and a use method of the rope ladder device. The rope ladder device comprises a rope ladder and a guide rail fixed on a maintenance iron tower or a utility pole, wherein the rope ladder comprises a pair of longitudinal parts and a transverse stepping part connecting the two longitudinal parts into a whole, the transverse stepping part comprises an external spiral loop and a steel wire rope arranged in the loop, each longitudinal part comprises a longitudinal soft rope and multiple sections of longitudinal sleeves arranged on the soft rope, two ends of the spiral loop are fixedly connected to the sleeves of the longitudinal parts on the two sides respectively, each sleeve is correspondingly connected with one spiral loop, a coil spring arranged in a closed box is arranged in each sleeve, one end of the steel wire rope in each loop is connected with one end of the corresponding coil spring, and the longitudinal parts are in sliding fit with the guide rail. The rope ladder device is simple in structure, and the rope ladder can be lengthened to be extended by the aid of the extendable transverse stepping part.