A gear rack type inertial container with a variable inertial coefficient is characterized in that a guide groove is arranged on a flywheel of the inertial container, a mass block capable of freely and radially moving in the guide groove is nested in the guide groove, and a magnetic sleeve ring is arranged at the axis of the flywheel and can suck the mass block to a position close to the axis of the flywheel when being static. When a pair of external forces oppositely acts at two endpoints of the inertial container, a rack indirectly drives the flywheel fixed onto a box to rotate, and centrifugal force enables the mass block to radially move, so that the inertial coefficient changes along with the movement state, impact generated in instantaneous action of high load is relieved, the dead weight of the inertial container can be reduced, and the inertial container is simple and practicable in structure.