The invention provides an environment-friendly automatic ink supply device. The environment-friendly automatic ink supply device comprises an ink box. The ink box is divided by an isolation plate into an upper ink conveying chamber and a lower ink storage chamber. The side wall of the ink conveying chamber is provided with a first liquid level sensor and a second liquid level sensor. The isolation plate comprises a first isolation plate body and a second isolation plate body which are arranged on the side wall of the ink box and are oppositely arranged, the upper surfaces of the first isolation plate body and the second isolation plate body are inclination faces, and an inverted splayed shape is formed by the two inclination faces. An electric gate is arranged at the junction of the inclination faces of the first isolation plate body and the second isolation plate body. A piston plate is arranged in the ink storage chamber and can move up and down along the side wall of the ink storage chamber. The first liquid level sensor, the second liquid level sensor and the electric gate are electrically connected with the controller. The ink supply process of the environment-friendly automatic ink supply device is automatic, ink can be conveyed to the position of an ink conveying roller only in the work state, ink is located in a closed cavity in the shutdown state and does not make contact with the outside, and environment pollution caused by ink volatilization is avoided.