Abstract: A multifunctional fitness chair includes an underframe, an armrest frame, an upper backrest frame, and a lower backrest frame. The underframe comprises left and right underframes, and underframe fixed shaft, and the armrest frame comprises left and right armrest frames and armrest fixed shaft, the left and right underframes are hinged on the left and right armrest frames, and the extension parts of the left and right armrest frames are correspondingly provided with left and right limiting plates which restrict the upward rotation of the left and right underframes. The upper backrest frame is fixed with an upper backrest shaft bushing, and at least two sets of symmetrically distributed upper backrests are arranged on the upper backrest frame. The lower backrest frame is fixed with a lower backrest shaft bushing, and at least two sets of symmetrically distributed lower backrests are arranged on the lower backrest frame.