A pen type safe blood taking needle is composed of a protective cap, a protective sleeve, a handle, a needle tube, a needle base, a spring, a blood blocking sleeve and a needle holder. An observationwindow is formed in the upper section of the needle seat, the protective sleeve is hidden in the handle, and the handle and the needle holder are mutually embedded and fixed; a protruding point is arranged on the outer side of the lower end of the protective sleeve, a warped part extending downwards and outwards is arranged on the opposite side of the protruding point, a pair of barb-shaped locking parts is arranged on the two sides of the protruding point, the locking parts can penetrate through opposite holes in the needle base wafer to be fixedly embedded in the needle base, and the springis compressed in a space formed by the needle base and the protective sleeve. During blood collection, the blood collection tube is inserted into the needle holder cylinder, so that the blood collection needle pierces the blood collection tube rubber plug, the blood collection tube cap can abut against the locking plate to move forwards, and locking of the spring is released; after blood samplingis completed, the spring resets to enable the protective sleeve to synchronously move forwards to cover the puncture needle tube and to be locked to prevent the puncture needle tube from being exposedagain while the needle is pulled out. The disposable puncture needle is simple in structure, convenient, safe, reliable and capable of being destroyed after being used, eliminating bloodstain splashing caused by retraction of the needle tube, eliminating puncture injuries and protecting medical staff.