Resources and environment carrying capacity is the basis for regional resources development and utilization as well as economic development strategy making and planning, which has already attracted large quantities of studies in academia. However, previous studies were inadequate in considering the connotation and restriction factors of resources and environment carrying capacity, and the evaluation indexes were not sufficiently connected with land planning (or regional planning). In the meantime, the indexes were treated in black box while neglecting the internal mechanism and coordinated development among systems. This study, took the Dehong Dai-Jingpo Autonomous Prefecture (Dehong Prefecture) in mountainous area of southwest China as a case. The paper evaluated the resources and environment carrying capacities of Dehong Prefecture and the five counties (cities) under its jurisdiction, and analyzed the mechanism and coordinated development of the nine sub-systems of resources and environment carrying capacity. The results showed that: 1) There is great regional difference of resources and environment carrying capacity in Dehong Prefecture. The resources and environment carrying capacities of Mangshi, Yingjiang and Longchuan counties are relatively high, and the carrying capacity of Lianghe County is at middle level, while the carrying capacity of Ruili is low. The five counties (cities) ranked as Mangshi > Yingjiang > Longchuan > Ruili > Lianghe in resources carrying capacity and ranked as Mangshi > Yingjiang > Longchuan > Ruili > Lianghe in environment carrying capacity. 2) The limitation analysis indicates that Ruili belongs to arable land-mineral resources limitation type, Mangshi and Longchuan belongs to mineral resources-geological environment limitation type, Lianghe belongs to arable land-urban construction limitation type, and Yingjiang belongs to water environment-geological environment limitation type. 3) Larger coupling relationship exists in resource-environmental system of Dehong Prefecture, especially the coordination degrees of urban construction system and geological environment system, forest resource system and atmospheric environment system, water resources and environment system, mineral resources system and atmospheric environment system are all above 0.96. The overall coordination degree of resources and environment in this region is up to 0.98.