Medical torque-adjustable screwdriver and assembling system of limiting circle thereof

The invention discloses a medical torque-adjustable screwdriver. The screwdriver comprises a handle, a screwdriver rod, a limiting circle, a ratchet wheel, an elastic member and an adjusting block; the handle is provided with a containing cavity; a screwdriver rod opening is formed in the front end of the containing cavity and an assembly opening is formed in the back end; an annular hump is formed in the screwdriver rod; the back end surface of the screwdriver rod is a ratchet wheel surface; the front end of the screwdriver rod protrudes from the screwdriver rod opening out of the containingcavity; the annular hump realizes axial limiting of the screwdriver rod; the limiting circle is sleeved on the screwdriver rod so the front end surface is attached to the back end surface of the annular hump; the limiting circle is fixed on the inner wall of the containing cavity to realize axial limiting of the screwdriver rod; the ratchet wheel surface is engaged with the ratchet wheel; the elastic member is positioned