The invention relates to a self-sealing venous indwelling needle provided with a coaxial outer casing tube. The self-sealing venous indwelling needle comprises an outer tube 1, an inner tube 2, a working liquid bag 3, an infusion cavity 4, a flexible connecting tube 5, a pressurizing block 6, a pressure-resistant liquid bag 7, lock catches 8, a needle seat 9, an infusion tube 10, a needle point groove 11, a tube bottom 12 and a liquid bag pipeline 13. The self-sealing venous indwelling needle provided with the coaxial outer casing tube is very simple to operate, tube sealing is finished under the condition that a working liquid is completely sealed, no pollutant enters, the needle can be used continuously without complications such as secondary injuries to veins, liquid leakage, phlebitis, venous thrombosis and the like, and a patient feels comfortable. Disposable syringes and flushers are not consumed, nursing operation steps are reduced, and the nursing efficiency and the nursing quality are improved.