The invention discloses a mechanical hand joint connection device. The mechanical hand joint connection device comprises a fixed disc with a central flat hole, a rotary disc with a central round hole,metal sheets with central flat holes, and a flat hinge pin; the flat hinge pin is sleeved with a disk spring after sequentially penetrating through the fixed disc, the middle metal sheet, the rotarydisc and the side metal sheet and then is locked and fixed through a fastener; a first joint arm is fixedly installed on the end surface of the outer side of the fixed disc through a fastener, and a second joint arm is fixedly installed on the end surface of the outer side of the rotary disc through a fastener; the rotary disc can generate frictional damping with the metal sheets in the rotating process, and the magnitude of the damping force can be adjusted by adjusting the pressing force of the disk spring. After the above structure is adopted, the mechanical hand joint connection device issimple in structure, damping is adjustable, through the skillful cooperative relationship, the safety and reliability are achieved, moreover, joints of a whole main arm mechanical hand can keep the accurate position posture, meanwhile, the rotation angle of the joints is conveniently detected through an angle sensor ingenious in design, and mechanical hand control is facilitated.