The invention discloses a thin-walled tube bending device and a thin-walled tube bending method, and belongs to the technical field of thin-walled tube bending. The thin-walled tube bending device comprises handles (1), fixing wheels (2), a connecting plate (3), butterfly nuts (4) and antiskid sleeves (5). The thin-walled tube bending device is characterized in that the fixing wheels (2) and the handles (1) are connected and fixed through splines, so that models of different types can be rapidly changed; clamping grooves (A) on the fixing wheels (2) have functions of fixing thin-walled tubes and preventing the thin-walled tubes from wrinkling; recessed groove design is adopted by the fixing wheels (2), and degrees are carved on the fixing wheels (2) to accurately control bending angles; the fixing wheels (2) are connected through the connecting plate (3) and fixed through the butterfly nuts (4); and the antiskid sleeves (5) are mounted on the handles (1). The thin-walled tube bending device and the thin-walled tube bending method have the advantages that wrinkling and cracking of tube walls caused during bending of the thin-walled tubes are avoided, and the device is simple to operate, convenient to demount and mount, free from limitation of operation places, labor-saving and low in cost.