Provided is a safety insulin pen needle, comprising a needle hub, a needle tube assembly base arranged on the needle hub, and a needle tube, and also comprising a trigger protector arranged outside the needle hub and a spring arranged between the trigger protector and the needle hub; a guide groove with a special structure is arranged on the side wall of the trigger protector, and a clamping column corresponding to the guide groove is arranged on the outer edge of the side wall of the needle hub, so that the trigger protector is in a to-be-triggered state before use, and is triggered only when in use, thus an injection needle can be protected from being exposed to the outside after use, and cross-infection caused by mistakenly touching or reusing is avoided. The safety insulin pen needle provided by the invention overcomes the defects that the traditional injection needle easily causes cross-infection due to no protecting device and the existing safety needle is inconvenient to use, has the advantages of simple structure and low manufacturing cost, and is suitable for being used by a patient for a long time.