The invention discloses an unbalance-load-free quick dismantling method for a multi-span concrete rigid frame arch bridge. The method comprises the following steps: erecting an old bridge demolition construction trestle platform, erecting an old bridge arch rib supporting frame, demolishing bridge deck accessories, demolishing bridge deck slabs, demolishing transverse tie beams, demolishing main arch ribs, demolishing bridge piers and demolishing bridge abutment. The unbalance loading of the middle pier is eliminated by erecting the arch rib support frame, the scientific demolition sequence isset, and reasonable dismantling equipment is used, so the defects of secondary cleaning, large construction potential safety hazard, heavy dismounting noise and dust, heavy secondary cleaning pollution and the like after integral collapse by using large-scale mechanical crushing or blasting in a traditional demolition method are overcome, dismounting can be carried out safely, efficiently and environmentally friendly, the green construction concept is met, the purposes of reducing noise, reducing pollution and reducing disturbance to the surrounding environment are achieved, the old bridge dismounting construction technology is enriched, and good reference significance is achieved for similar projects.