The invention discloses a single-ring flexible piece parallel clamping self-adaption robot finger device, and belongs to the technical field of robot hands. The device comprises a base, a first finger section, a second finger section, a near joint shaft, a far joint shaft, a drive, a first transmission wheel, a second transmission wheel, a flexible transmission piece, a convex block poking disc, a poking wheel, a transmission mechanism, a first spring piece, a second spring piece and a limiting convex block. The device uses the drive, the flexible piece transmission mechanism, two spring pieces, the convex block poking disc, the poking wheel, the limiting convex block and the like for realizing the finger functions of parallel clamping and self-adaption grabbing; the second finger section can flatly move to hold an object or outwards expand to support the object, or the first finger section and the second finger section can rotate in sequence to self-adaptively wrap objects with different shapes and sizes; and the device is wide in grabbing range and stable and reliable in grabbing, only uses one drive for driving two joints, needs no complex sensing and control systems, and is simple in structure, small in size, light in weight, low in machining, assembly and maintenance costs and suitable for the robot hands.