As a new method of basin sedimentological research, the process-response theory is based on the earth system science. This kind of method is composed of process research and response research. The controlling role of the basin evolution in the sedimentary process is emphasized in this theory. The process-response theory was successfully applied to the study of lacustrine carbonate rocks in the 4^th member of Shahejie Formation (Es₄) within the mid-northern part of the western sag of Liaohe depression. The results show that the formation and distribution of lacustrine carbonate rocks are obviously controlled by basin evolution process in time and space. Based on the study of the Es₄ in the mid-northern part of the western sag of Liaohe depression, the authors hold that the sedimentary environment of lacustrine carbonate rocks has three key points. The first one is the suitable topography and hydrodynamic conditions. The second one is the favorable climate and water media, and the last one is the rich provenance supply and the dolomitic conditions. The application of the process-response theory, together with the research on the three key points and the comprehensive sedimentary model of lacustrine carbonate rocks, constitutes the basis for establishing the composite sedimentary model with more reference and guidance value.