Abstract: “IIYouhang No.1” is a new variety by the Space-Flight. The cultivated area of “II Youhang No.1” is 266,700 hm2 from 2003 to 2005, the total yields were about 120 million kg in three years. Its characteristics was super-high yield, high quality, cold tolerance in seedling stage, high temperature tolerance at heading stage、large panicles、more spikelets, high setting rate, wide adaptability and strong ratoon ability. It was registered in Fujian province Crops Variety Approval Committee and the National Crops Variety Approval Committee in 2004 and 2005 respectively, and approved in Guangxi province in 2005. It was one of those super-hybridization varieties (combinations) to be demonstrated and extended in national wide and Fujian province. The extension and application, botanical traits and yield components of “II youhang No.1” have been summarized in this paper, and its yield, resistance and quality in provincial trials, producing trials and high yield demonstration under an area of 6.67、66.67、666.67 hm2 also have been introduced.