Urban green spaces are looked upon as the last remnant of nature in urbanized areas. They play a pivotal role in environmental and ecological changes, and furthermore can decide whether we can have a sustainable development in the urban area. With the urban growth, green spaces varied in the area, type and spatial pattern. To optimize urban green space in the future, it is necessary to understand the driving forces on the processes of urban green space changes. In this study we chose Jinan City as a case study. We analyzed the process of urban green spaces dynamic from 1996 to 2004. During this period, a significant increase of the total area of urban green spaces took place. However, the growth rate of different green space types was not the same. To better link the spatial pattern change with the process, a gradient analysis was conducted in 4 directions combined with landscape metrics. Based on the spatiotemporal change of urban green spaces, it could be concluded that urban greening policies and urban sprawl were the main driving forces.