A disposable automatic retracting safety syringe with a replaceable syringe needle comprises an outer sheath, a core rod, a dispensing syringe needle and an injection syringe needle. The dispensing syringe needle is shaped in plastic material and can be replaced by the injection syringe needle according to use requirement, so as not to make the syringe needles deformed or influence smoothness and sharpness due to medicine dissolution to cause bad influence on human body injection. Without changing the conventional operation habit in use, the safety syringe is convenient to use and has reliable effect. After injection is completed, the syringe needles can be retracted and hidden by an automatic retraction mechanism to guarantee that medical personnel avoid suffering from being accidentally damaged by dirty needle point, and the core rod is blocked by a blocking basket from retracting so that the used syringe cannot be used repeatedly for injection. This realizes disposable use of syringe in the true sense and avoids cross spread of blood-borne diseases. The safety syringe has a pressed compression spring arranged around a retraction rod, and has more reasonable structure design so as to be more suitable for automatic assembling production of a production line. It has high quality, high qualification rate and lower cost.Linvention porte sur une seringue de sécurité à rétraction automatique jetable ayant une aiguille de seringue remplaçable, laquelle seringue de sécurité comprend une gaine externe, une tige principale, une aiguille de seringue dadministration et une aiguille de seringue dinjection. Laiguille de seringue dadministration est façonnée en matière plastique et peut être remplacée par laiguille de seringue dinjection selon une exigence dutilisation, de façon à ne pas amener les aiguilles de seringue à se déformer ou à influencer la régularité et le caractère tranchant par suite dune dissolution de médicament pour provoquer une mauvaise influence sur une inje
