Implementation of environmental education programs in nature reserve areas in southwestern China faces challenges because of a highly exam-oriented educational system and financial constraints. We examined a relatively successful case at the Caohai Nature Reserve in Guizhou by analyzing its development from 1993 to 2014. Results suggest that long-term local social capital constructions have contributed to the strongly cooperative relationship among international nongovernmental organizations (NGOs), nature reserve staff, farmers, and local schools. Relationships of trust have created a positive atmosphere for environmental education development in later stages. Reflecting on the current implementation, we identify five future goals.