Abstract: Institutional ecological folk custom refers to ecological folklore primarily characterized by institutional rules, falling within the realm of informal institutions. It exhibits distinctive features such as being normative, supplementary and adjusting and other typical characteristics when compared to conventional ecological folk customs. According to the targeted adjustment objects and regulatory purposes, institutional ecological folk customs in Xiangxi of Hunan Province can be divided into three major types. Firstly, natural taboo type of ecological folk custom primarily adjusting the relationship between "man and God", exemplified by the Miao nationality's taboo on cutting maple trees; secondly, the villager's conventional type of ecological folk custom mainly adjusting the relationship between "man and man", exemplified by the Miao Nationality's Langgui Treaty prohibiting cross-border tree logging; thirdly, the technical rule type of ecological folk custom primarily adjusting the relationship between "man and nature" , exemplified by the Dong nationality's folk custom of "intercropping of forest and grain" . In the new era of ecological civilization, there is a need to enhance cultural awareness of institutional ecological folk custom and promote the creative transformation and innovative development of traditional ecological culture among ethnic minorities in Xiangxi, Hunan Province.