Abstract: This paper took Lincang City as the research area,and constructed the ecological security pattern system of Lincang City with the minimum cumulative resistance model based on the ecological source determined by the results of ecosystem service evaluation. Firstly,through the evaluation of the importance of ecosystem services and ecological sensitivity,Lincang city's extremely important and sensitive areas were taken as the source of MCR ecological security pattern construction,and the resistance surface of ecological source expansion was constructed by considering the distance from residential areas,roads and river systems,land use,vegetation cover,topographic factors and so on. The weight of each resistance surface was determined by analytic hierarchy process（ AHP）,and the comprehensive resistance surface of ecological source expansion in Lincang City was calculated. Based on the natural fracture method,the comprehensive minimum cumulative（ cost） resistance surface of spatial resistance movement of ecological source was clustered and the ecological land under three safety levels in Lincang City was divided. The area of ecological land with low security level is 214. 25 km²,accounting for 8. 57% of the total area of the region. The ecological land area at the middle safety level is 7610. 41 km²,accounting for 32. 22% of the total area of the region. The area of ecological land with high security level is 13985. 49 km²,accounting for 59. 21%of the total area of the region. Through ecosystem service assessment,identification of ecological sources,construction of MCR comprehensive resistance surface,identification of ecological corridors and ecological sources,the ecological security pattern of three barriers and one belt area in Lincang City was finally constructed. Three barriersare the natural barrier of Nangong River Nature Reserve as barrier for biodiversity protection in Lincang City,which isthe central YongdeDaxueshan Ecological Barrier Area and the western Zhenkang Border Ecological Protection Barrier Area in Cangyuan County and Gengma County. One belt is along the Lancang River Water Conservation Protection Zone,and distributed along the water conservation area of Lancang River from north to south.