A needle gradually auto-retractable safety medical syringe includes a hollow barrel, a plunger provided in the barrel, a piston provided on the head of the plunger, a hub provided on the head of the barrel. The hub includes an elastic connecting hub providing with a needle and a hub sheath for fixing the elastic connecting hub, the elastic connecting hub may be disengaged with the head of the barrel and retracted with the effect of a spring after having finished the injection, a regually retractable bracket which are integrated with each other, the regually retractable bracket forms with at least two elastic supporting claws engaged to the inner wall of the pushing tube of the front end of the plunger after the injection finished, the elastic connecting hub allows the regually retractable device to retract in the barrel with the effect of the spring, and allows the needle to be drawn into the barrel.