Landscape ecological security can reflect the relationship between regional ecological protection and economic development. It is of great significance to understand the pressure on the ecological environment and alleviate the contradiction between human and land. Based on the remote sensing image of 2005, 2010, 2014 and 2017 as the data source combined with field survey to verify the images, we used the ArcGIS and landscape pattern index method to construct landscape ecological security index to analyze the evolution of landscape pattern and the spatio-temporal differentiation laws of ecological security in the trough valley area. Therefore, an environment-friendly land use combination model is proposed. The results were as follows:(1) from 2005 to 2017, the overall landscape pattern of trough valley area presented fragmentation, the number of landscape patches increased, the landscape pattern changed from single regularization and simplification to complex and mixed type, the diversity increased and the spatial heterogeneity enhanced. With the variation of time, the overall landscape ecological security in karst trough valley showed an upward trend,the Ecological Security Index (ESI) of the western and eastern trough valleys increased from the trough basin to the two sides of the hillside, while the middle trough valley increased from the hillside to the trough basin. (2) At a research scale of 200 m,the global positive correlation of ESI in the western trough valleys is the most significant, and its Moran's I value showed a trend of first increased and then decreased,but the middle and eastern troughs were the opposite.The spatial agglomeration pattern of ESI in karst trough valley area was mainly manifested as high-high and low-low value agglomeration areas, and the spatial agglomeration degree was higher, while the distribution of high-low and low-high agglomeration areas was less and its change was not obvious.(3) The landscape agglomeration distribution pattern is influenced by low topographic relief and low slope that presents similar trend of inverted "U" shape, while the elevation is opposite. (4) The landscape pattern of karst trough valley area can increase the landscape ecological security by expanding the land use combination pattern of "woodland-shrub woodland-grassland". (5) The spatio-temporal differentiation of landscape pattern and its ecological security is the result of the joint action of the local natural environment, social economy and policies. We can provide scientific reference for regional scientific decision-making by analyzing the driving mechanism of multiple factors on landscape pattern and ecological security evolution trend of trough valley area.