A needle protection device and a safety needle assembly comprising the needle protection device. The needle protection device comprises a connecting portion (2) and a protection arm (6) rotatable relative to the connecting portion (2). A pair of holding members (51 52) are respectively formed on a proximal end portion (62) of the protection arm (6) and the connecting portion (2) and configured to engage with each other in an unretreatable manner. A pair of positioning arms (71 72) are respectively formed on the proximal end portion (62) of the protection arm (6) and the connecting portion (2) and formed with at least one pair of complementary snap fitting features (711 723 712 723 713 724). The paired snap fitting features (711 723 712 723 713 724) are configured to engage each other in a separable manner. The needle protection device and the safety needle assembly can not only reliably prevent medical instruments such as syringes from incurring accidental needle sticks after use and ensure such medical instruments disposable but also exhibit a simple structure and low costs. Additionally during transport and use of the safety needle assembly the needle protection device can be stably positioned at various desired positions.
