The invention discloses a semi-active variable-stiffness energy dissipation and seismic mitigation control anchor bolt. The anchor bolt consists of a controller (1), a communicating line (2), a sensor (3), a variable-stiffness control device (12), a sleeve (20), a hollow anchor pipe (5), an anchor gear (10), an anchoring spring (11) and a support structure (4), wherein the variable-stiffness control device (12) consists of a hydraulic cylinder (13), a dual-striking piston (14), oil (16), a bypass pipeline (17), an electro-hydraulic servo valve (18), a stiffness spring (19a), a stiffness spring (19b), and a support box (21) and a base plate (22) connected through a bolt (23). According to the semi-active variable-stiffness energy dissipation and seismic mitigation control anchor bolt, the unrecoverable problems of excessive deformation of an anchoring and shotcreting support structure, unavailable self-adjustment of the support structure, even damages and the like caused by seismic actions are solved, and the seismic resistance of the anchoring and shotcreting support structure and the safety stability of a support body are improved.