The invention relates to a rotary-type self-latching safety braking device and a working method thereof. The rotary-type self-latching safety braking device comprises a rotating wheel, an axle, an axle base, a movable pin key and a pin key resetting device. An inner cylindrical surface of the rotating wheel, which is matched with the axle, is provided with a plurality of key slots. The axle is provided with a radial sliding chute which is internally provided with the movable pin key and the pin key resetting device. During the slow rotating process of the rotating wheel, the movable pin key makes slow radial
reciprocating motion in the radial sliding chute of the axle correspondingly, and the axle can normally rotate; and when the rotation speed of the rotating wheel suddenly increases, the
reciprocating motion of the movable pin key is damaged, one end of the movable pin key is propped into the key slot of the rotating wheel, and the rotating wheel is self-latching braked immediately. The invention has compact structure, simple construction, small volume, good sealing property, sensitive action, high reliability, short
braking distance and safe use, and is applicable to the
engineering fields such as building, machinery,
metallurgy, mining, vehicles, vessels and the like. When in normal work, the rotary-type self-latching safety braking device slowly runs; and when in dangerous situations, the device fast runs, and the self-latching safety braking device in running is stopped immediately.