Based on RS and GIS technology, taking typical Jining City in Nansi Lake watershed as the study area, this paper analyzed land use change in Jining City from 1987 to 2008, and then an evaluation index system was established on basis of “Hazard-State-Immune” model. The results of the study were as follows: 1) the change of land use in study area from 1987 to 2008 was great, and had typical regional characteristics; 2) in the past 20 years, ecological security in study area changed from deterioration to improvement, experiencing V-shaped process, and the main reasons of improvement since 2000 were implementation of the South-to-North Water Transfer Project as well as enhancement of ecological construction; and 3) the spatial difference of land ecological security in research area was obvious, the best places were located in the eastern hilly area and Nansi Lake, the worst places were located in the middle area, and the remaining areas were in a warning state.