The utility model provides a scalable portable string of ladder, includes supporting legs, extensible member, mounting and telescopic joint, the supporting legs is H shape structure, the extensible member includes a horizontal pole and two spinal branch poles, both ends are connected respectively about the horizontal pole branch, the top of supporting legs is connected through the horizontal pole,install the multisection extensible member on the horizontal pole on supporting legs top, supporting legs and branch are hollow pipe structure, and in the branch of lower floor's extensible member was inserted to the branch of upper extensible member, the branch of lower floor extensible member was inserted to the supporting legs in, the mounting is fixed branch when the extensible member expandes, prevents that the extensible member from returning to move back, the telescopic joint is the sleeve type telescopic festival, is made by insulating material, and the cover is on the top of branch and supporting legs, as between the two spinal branch poles and the insulating part between branch and the supporting legs. The beneficial effect of the utility model: it is scalable to hang the ladder, when need not to use, can return all extensible members and move back, reduces to hang the area occupied of ladder, conveniently carries.