The invention provides a platform maintenance ladder for a disconnecting switch and relates to climbing tools for substation maintenance of electric power systems. By the adoption of the platform maintenance ladder for the disconnecting switch, the problems that during maintenance work of the disconnecting switch, certain potential safety hazards exit when a ladder is used, and work through a crane is not flexible enough are solved. Stand columns are all vertically arranged, and footboard beams are fixed to the side walls of the stand columns; an operation footboard is fixed to the footboard beams; the two ends of the open side of a protective frame are connected to the first stand columns correspondingly, and the protective frame can rotate around the connecting points; the third stand columns are connected with the bottom ends of the first stand columns and the bottom ends of the second stand columns correspondingly, and connecting beams are fixed to the adjacent third stand columns correspondingly; fixing through holes are formed in a fixing beam, one end of adjustable screws are connected to the connecting beams, and the other ends of the adjustable screws penetrate through the two fixing through holes to be connected with the fixing beam. The platform maintenance ladder for the disconnecting switch has the beneficial effects of being high in safety performance and flexible in operation. The platform maintenance ladder for the disconnecting switch is suitable for being fixed to a framework of the disconnecting switch to be maintained.