Safety protection shell for safety shell type injector

The utility model discloses a safety protection shell for a safety shell type injector. The safety protection shell comprises a sleeve ring and a needle pipe protection shell, wherein 6-8 clamping teeth are uniformly distributed on the inner circumference surface of the sleeve ring; the needle pipe protection shell is hinged with the sleeve ring and is provided with two side walls and a longitudinal opening formed in a rear wall between the two side walls; a needle pipe seat limiting arm group, a first needle pipe limiting arm and a second needle pipe limiting arm are sequentially arranged in the longitudinal opening of the needle pipe protection shell from the near end to the far end; the needle pipe seat limiting arm group comprises two limiting arms in bilateral symmetry. The safety protection shell can be added to any conventional injector to form the safety shell type injector and is favorable for cost control; furthermore, compared with other safety injection needle type products, the safety protection