The invention discloses a connecting rod belt wheel stepless variable coupling self-adaptive robot finger device, and belongs to the technical field of robot hands. The connecting rod belt wheel stepless variable coupling self-adaptive robot finger device includes a base, two finger sections, two joint shafts, two motors, a connecting rod transmission mechanism, a belt wheel transmission mechanism, a self-locking transmission mechanism, a spring part, a limiting block, a pushing plate and the like. According to the device, functions of coupling gripping and self-adaptive enveloping grasping ofdouble-joint robot fingers are comprehensively achieved, namely, a small-size object can be gripped by two finger sections through coupling linkage, grasping is quick, and objects with different shapes and sizes can be self-adaptively grasped by sequentially rotating the first finger section and the second finger section in an enveloping mode; the coupling ratio can be adjusted, switching is conducted between properties of object quick grasping and grasping in a large range, better grasping stability can be achieved, and the grasping range is large; and an underactuation mode is adopted, a motor is used for driving two joints in grasping, a complex sensing and control system is not needed, the device is compact in structure, small in size, light in weight and low in manufacturing cost andmaintenance cost.