Abstract: Nanometer is a measurement unit of length, also named as millimicron （one millionth of a millimeter）. Nowadays, nanotechnology has been applied in many industries, such as nanophysics, nanoelectronics, nanobiology, nanochemistry, nanometrology, nano-machining. The nanotechnology applied in pharmacology field was named as nanopharmics. The nano-particles applied in pharmacology included nano-drug carrier and nano-medicine preparation. The nano-drugs had low production cost, high efficiency, high automation degree and large scale. And the nano-drugs realized organ targeting, high efficiency, low toxicity and other revolutionary breakthrough. The nano-drugs had advantages of good stability, small stimulation to stomach and intestines, etc. Therefore, nano-drugs had a broad development foreground in industry field and medical field in the world. The research and application of nanotechnology in medical field were reviewed.