Venous catheter with automatic deployment

The invention discloses a venous catheter with an automatic unfolding part, the venous catheter comprises a catheter main body and the automatic unfolding part, and the catheter main body is provided with a blood sampling hole; the automatic unfolding part is arranged on the catheter body and comprises a contraction state and an unfolding state, in the contraction state, the automatic unfolding part is close to the catheter body, or the automatic unfolding part retracts into the blood sampling hole, in the unfolding state, the automatic unfolding part protrudes out of the blood sampling hole, and a gap is formed between the blood sampling hole and the blood vessel wall. The automatic unfolding part can be unfolded automatically, expansion can be realized without filling liquid or gas, so that a liquid or gas channel does not need to be arranged on the venous catheter, and the blood collection device is convenient to use. Therefore, the structure of the venous catheter can be simplified, in the using process,