The invention discloses an electromagnetic rack pushing type safety braking device of a lifting device. A movable rack is electromagnetically pushed to horizontally move on a rail or keep at certain determined positions. The top of the movable rack makes direct contact with a main bearing structure of a lifting device lift car after entering a braking state for bearing or makes contact with the main bearing structure through a middle transition bearing part for bearing. A operation mechanism for the movable rack operates the movable rack to horizontally move on a rail hole or stay and keep at certain determined positions, wherein the determined positions include a braking position engaged with a drive rack of the lifting device or a free position completely disengaged from the drive rack of the lifting device and having a certain gap with the drive rack. Electromagnetic rack pushing type safety protection braking is adopted, so that the beneficial effects that the flat layer precision is obviously improved, and the safety protection braking quality is obviously improved are achieved.