The utility model relates to a safe internal arteriovenous fistula puncture needle cap for hematodialysis. The puncture needle cap comprises a hollow needle cap pipe sleeved outside a puncture needle, wherein two parallel gap slides allowing two needle wings of the puncture needle to penetrate out are formed on the wall on one side of the needle cap pipe; when the needle wings are pushed to the tops of the slides, a puncture needle head stretches out of the hollow needle cap pipe; and when the needle wings are pushed to the tail ends of the slides, the puncture needle head shrinks into the hollow needle cap pipe. The needle cap is simple and rational in structure, safely and conveniently operated, and good in using effect; when a needle is withdrawn, the needle cap pipe seals the puncture needle head, and the puncture needle head is not exposed, so that accidents that people are punctured in the working processes of separating objects used for the hematodialysis, cutting the puncture needle head, putting the puncture needle head in a sharp instrument container and the like in the prior art are reduced, the labor is saved, phenomena that because a needle head punctures an outer packing bag, transportation personnel is damaged, and the environment is polluted are avoided, and the puncture needle cap is suitable to be popularized and applied.