A spring hinge comprises a frame leaf, door leaf, upper and lower tube sections to fixedly connect with frame leaf, and middle tube section to fixedly connect with door leaf, wherein middle tube section is internally made with a hydraulic damping speed reducing device; lower tube section is internally installed with a torsion spring device, wherein torsion spring being completely sleeved on the exterior of spindle rod is affixed to the spring seat at the lower end thereof, and an upper and lower clutching device is installed between middle tube section and torsion spring device thereby allowing middle tube section and torsion spring device to be separated or combinedly moved, wherein torsion spring and hydraulic damping speed reducing device are packagely used to close door slowly while releasing spring energy after closing to set angle to precisely close the door.