An air joint type flexible mechanical arm based on rope drive comprises a machine base, three motors, a power source, a control system, an arm body mechanism, a tail end actuator and a driving rope. The machine base is a shell body. The motors, the power source and the control system are arranged in the machine base. The arm body mechanism is formed by connecting a plurality of sets of joint units which are the same in structure in series. One end of the arm body mechanism is connected to the machine base, and the other end, that is, the tail end of the arm body mechanism is connected with the tail end actuator. Each joint unit comprises end covers, an air bag, sliding sleeves, clamping rings, a drawing wire and air nozzles. The arm body mechanism can be manually filled with gas through each joint unit and achieves connecting and supporting effects, and the arm body mechanism also can be manually compressed and folded by releasing gas of each joint unit, so that packaging and transportation are convenient. The air joint type flexible mechanical arm based on rope drive has the advantages of being good in flexibility, light in mass, large in bearing capacity, capable of being folded and convenient to package and transport.