A mobile chair for a critical patient is characterized by comprising supporting legs, a seat cushion, a backrest, arm exercising assemblies, a leg exercising assembly and a supporting mechanism, wherein the seat cushion is arranged at the tops of the two supporting legs, the backrest is installed on the rear side of the seat cushion in a hinged mode, a cross rod is arranged at the top of the backrest, a vertical shaft at the bottom of the cross rod is rotatably installed in the backrest, and a coil spring is arranged between the vertical shaft and the backrest. The arm exercising assemblies are arranged on the left side and the right side of the seat cushion respectively, each arm exercising assembly comprises an armrest, supporting rods, a rotary shaft, a torsional spring and a supporting shaft, the two ends of the rotary shaft are rotatably installed on the supporting shaft, the torsional spring is arranged between the supporting shaft and the rotary shaft, and a constraint belt is arranged on the armrest. The leg exercising assembly is arranged at the bottom of the seat cushion and comprises swing plates, pedals, a pedal supporting plate, screws and pedal springs. The supporting mechanism is arranged between the seat cushion and the backrest and comprises an outer rod, an inner rod, an inner rod spring and a positioning block. The mobile chair for the critical patient can bring convenience to the critical patient for physical exercise activities.