The present invention discloses a holster with a protection mechanism that facilitates holstering and unholstering and protects against theft and robbery, comprising: a waist protection plate, a holster body, a positioning supporting plate, an L-shaped connecting piece, and a positioning supporting clamp. A pressing member is disposed at a side close to the waist protection plate. A positioning column fixes and tightly locks the L-shaped connecting piece with the holster body by inserting gaskets and an E-shaped washer into a clamping slot. The L-shaped connecting piece and the positioning supporting clamp cooperate with each other in space according to a lever principle, and an overall trigger mechanical structure is simple, low in failure rate and relatively reliable in actual applications.