Abstract: Dynamic changes in farmland landscape in Jilin Province in the past 50 years were analyzed from the prospect of landscape ecology,e.g.crop habitat diversity index,crop pattern diversity index and crop species diversity index.By analyzing changes in acreage of farmland stricken by drought,flood,wind and hail,frost,crop diseases and pests,and dynamics of the ratio between the acreage of disaster-stricken farmlands and the acreage of disaster-affected farmland since 1978,it was discovered that the diminishing landscape diversity is one of the main causes of the frequent occurrence of agricultural disasters and the increase in loss.It is suggested that diversified arrangement of agricultural productions be the general orientation for future agriculture so as to minimize the loss caused by agricultural disasters.