The landscape structure in west Jilin province has undergone great change, and consequently the ecology and environment has been deteriorating. It is significant to study on the landscape dynamics and responses of ecological security to it, By the use of the software of ARCGIS, dynamic changes of the landscape gradients, landscape structure, conversion processes of the landscape gradients and responses of ecological security were studied after the collection of the land use data from the study area during long term. It showed that landscape elements had experienced great change; Fragmentation of landscape was increasing and connectivity were cut down; Agricultural policy and demands were the major driving force, the change of hydrology and environmental factors also played an increasingly important role in landscape dynamics. Irrational landscape changes brought serious problems of ecological security, The paper provided suggestions for further research on responses of ecological security to landscape dynamics.