Structurally improved safety syringe

The utility model relates to a safety syringe with an improved structure, which is characterized in that the front end of a syringe body is provided with a plurality of ditch grooves, the surfaces of the outer edges of which are provided with convex tracks, the front ends of which are additionally provided with a traction power plate and a clamping block, wherein, the traction power plate is slightly higher than the convex tracks of the back side. The back end of a protective syringe is provided with a sheathed hole, the internal diameter of which is provided with a first clamping hook, a second clamping hook and a third clamping hook which are symmetric up and down. The outer edge of the protective syringe nearing to the sheathed hole is also provided with an opposite traverse movable groove. The first clamping hook is extended with a guide track toward front. The convex tracks can be moved in the guide track, and thereby, the syringe body can realize telescopic displacement in the protective syringe. A syringe has more safety and practicality by the utility model.