The invention discloses an integrated fully-automatic blood sampling instrument. The integrated fully-automatic blood sampling instrument comprises a support rack, a needle inserting mechanism, a driving mechanism, a sampling unit and an electric rotary knob, wherein the sampling unit is composed of a sampling needle, a hose, a suction blood drainage joint; the suction blood drainage joint is composed of a blood drainage channel, an air suction channel, a blind shaft hole and an air hole; the blood inlet of the blood drainage channel is connected with the hose, and the blood outlet of the blood drainage channel is provided with a blood drainage needle; one end of the air suction channel is provided with an air suction needle, and the other end of the air suction channel is provided with anair suction orifice; the blind shaft hole is provided with an axially limited rotary shaft valve; in an initial position, a rotating shaft unit is matched in a sealed mode with the blind shaft holeand blocks the blood drainage channel; in a blood drainage position, a first channel communicates the blood inlet and the blood outlet, a second channel communicates the air suction needle and the airsuction orifice; in a drip-proof position, the first channel communicates the blood drainage needle and the air hole, and the second channel communicates the air suction needle and the air suction orifice. Therefore, the integrated fully-automatic blood sampling instrument thoroughly solves the problem of blood dripping leakage during blood sampling and meanwhile avoids blood dripping after everydetected user completes blood sampling and takes down the blood sampling needle. Besides, the invention also provides a corresponding blood sampling method.