Ecological security assessment is important for poverty reduction and environmental protection in large poor areas in Lipan Mountain in Ningxia Hui Autonomous Region. Based on data from 2001 to 2011, press-state-response(PSR) model was used to construct index system which consists of 19 indicators in this research and entropy method was used to calculate ecological security index value of seven poverty counties in Liupan Mountain area. The results were as follows: (1) On the time scale, it can be classified as three phases: during 2001 and 2006, ecological security index value slowed down and to be lowest in 2007 and 2008, and then began to rise slowly, showing that the study area had taken a turn for the better after a period of deterioration. (2) On the space scale, it can be classified as four areas: ecological security index values of Pengyang, Longde and Jingyuan County are higher and stable; while ecological security index values of Xiji and Haiyuan County remained at a low level; ecological security state of Yuanzhou District improved gradually, and its ecological safety in 2011(0.5282) was only next to that in Pengyang County(0.6194); Moreover, ecological security index value of Tongxin County decreased, but still kept higher than that of Xiji and Haiyuan County.