The data in this study were mainly from IKONOS images produced in USA. The methods adopted were geometric rectification and other image processing means through ENVI, manual and computer image interpretation through MapGIS and its automatic area measuring. In this way, the green area of Yueyang City was accurately figured out. This result shows that the greening ratio of Yueyang City has reached the national standard of gardenized city and that the city still has a great development potential in this aspect. The utilization of its water areas and peripheral forests seems to be a fast and economical way for further gardening this city. Yueyang City should set the strategy of becoming an international gardenized city.