The ‘No. 1 Central Document’ issued in 2016 pushed the ‘three rural issues’ to the cusp. As an important component of the agricultural landscape, the features of the farmland landscape would directly affect the inside ecological processes and productivity of cultivated land, so as to finally decide whether the food problem of the 1.3 billion people in China can be solved or not. In order to investigate changes in the ecological environment of cultivated land in the Karst mountain area on the basis of landscape ecological security theory, the farmland of Chishui City (Guizhou Province, China) was selected as the research object in this essay. Firstly, datas like patch density, patch shape index, patch fractal dimension and patch stability factor were picked out and be used in order to analyse the characteristics of landscape patch evolution and spatial distribution of landscape pattern in the Karst mountain area. Secondly, a landscape ecological security evaluation model for farmland in the Karst mountain area should be constructed to analyze the evolution of the cultivated land's landscape ecological security from 2000 to 2004. In this step, ecological security index, patch proximity index, patch fragmentation, patch boundary fragmentation, landscape type patch dominance index, separation index, and landscape fragile index were used. Thirdly, on this basis of the past two steps, the centroid method commonly used in geography and economics was introduced to calculate the gravity center of the landscape ecological security of cultivated land. In the same time, both the gravity transfer distance model and the moving direction model were used to measure the distance and direction of the ecological safety center of cultivated landscapes. Finally, to explore the driving factors of ecological safety evolution and center of gravity shifts based on regional characteristics, 10 indices were selected, namely, population density, proportion of agricultural population, rate of regional construction land, grain yield, unit of cultivated land fertilizer, arable area, gross output value of agriculture, per capita disposable income of farmers, crop sown area, and number of rural practitioners, and a grey correlation analysis was performed for changes in the indices and changes in the ecological security indices of the cultivated landscape. The results showed as follow. Firstly, in the recent 15 years, the ecological security center of gravity of cultivated land landscape in Chishui moved to the Northwest. Meanwhile the patch density, fractal dimension, and fragmentation decreased, the patch shape index and connection degree increased. The shape of the cultivated land gradually changed to a complex state, and the distribution tended to be homogeneous, whereas the patches became increasingly clustered. Secondly, arable land continued to decline, ecological safety decreased. According to the landscape ecological security index of cultivated land calculated results, it could be seen that the ecological security zone of dry land landscape was expanding to the southeast, and the safe areas was changed to the the relatively safe areas, and the relatively safe areas was changed to the dangerous areas; The relatively safe areas of paddy field landscape changed from a centralized distribution to a divergent distribution, the safe areas transformed the relatively safe areas and hazardous areas. The ecological security of dry land and paddy field landscape was not optimistic. Thirdly, the gray analysis results indicated that the driving factors that affect the evolution of landscape ecological security and the transfer of gravity in dry land of the study area were obtained, and the maximum was the total agricultural output value, followed by grain yield and crop sown area. Grain yield was the most important factor affected by the evolution of landscape ecological security and gravity transfer in paddy fields, followed by the level of fertilizer application and population density.