UV (ultraviolet) sensor is widely used in many fields such as missile early warning, spacecraft autonomous navigation, global positioning and so on. Comparing with other semiconductor based UV sensor, ZnO nanowire (NW) UV sensor have many unique advantages including visual light blind, biocompatible, low cost and so on. But, two main shortages, low photo response () and long recover time, embarrass the application of single wire ZnO UV sensor. In this paper, we introduce the working principle of ZnO NW UV sensor and expound some methods for increasing photo response, enhancing sensitivity and shortening response and reset time of ZnO NW UV sensor. Besides this, we introduce a kind of UV sensor fabricated by integrated ZnO NWs recently. The photo response of this UV sensors reaches the order of mA, when exposed to UV light at 4.5 mW/cm2. It also has perfect stability and reliability. Because of these properties, this new kind of UV sensors has a great potential for application.