Hydraulic wrist developer

The invention discloses a hydraulic wrist developer. The hydraulic wrist developer comprises an elastic cavity, a signal control assembly arranged in the elastic cavity, and a force application mechanism used for switching on or off the signal control assembly. The signal control assembly controls switch-on and switch-off of a prompt signal. The force application mechanism comprises a hydraulic buffer, a reset spring and a stress support. According to the hydraulic wrist developer, light emitted by a vibrating light-emitting diode is adopted as the prompt signal, whether the grasping force of a blood donor is proper or not is visible, and the blood donor can timely adjust the force; the interval at which the reset spring drives a buffer rod of the hydraulic buffer to slowly retract is adopted as the frequency at which the blood donor grasps the wrist developer, thus, the blood donor can accurately apply force, vasospasm is avoided, and the blood drawing efficiency in a hospital is improved.