Abstract: With the rapid development of modern science and technology, the application of nanomaterial is ubiquitous in our daily life and medical field, in which the application related to nano-silver is more extensive. On one hand, it can make positive effects, such as anti-bacteria, anti-virus, anti-fungi, anti-parasitic infection and anti-tumor. In particular, its anti-bacterial activity in some acute or chronic treatment of infected wounds is more prominent. The application in diseases of gynecology, orthopedics, cardiovascular system, oral cavity, and ophthalmology is increasing. On the other hand, it can induce negative impacts and potential toxicity. It can be harmful to skin, gastrointestinal tract, respiratory tract, cardiovascular system, and so on. This article summarizes the antimicrobial application of nano-silver on treatment of diseases, its potential toxic effects on some organs or systems, and the possible toxic mechanism, as well as makes prospects of the research trends of nano-silver in future.