To explore butterfly community diversity in Fenglin National Nature Reserve,butterflies were investigated with the line transect method inside and outside the reserve from June to August each year from 2016 to 2018.A total of 15 083 butterflies were observed,of which 99 species in 60 genera under seven families were identified.Nymphalidae was the dominant family,with the most number of genera,species and individuals.There were 5 dominant species,19 common species,57 unusual species and 18 rare species.Nymphalidae had the highest diversity index and richness index,Papilionidae had the highest dominance index and Parnassiidae had the highest evenness index.There was a significant difference in diversity of butterflies among habitats,with the diversity index being the highest in medium altitude core area and the lowest in high altitude experimental area.The diversity index of butterflies had a significant positive correlation with their richness index in all habitats (r=0.9971,P<0.001).The dynamic trend of species number,the diversity index and the richness index was consistence,being the highest in July and the lower in June and August.The community similarity coefficient of species was 0.8 inside and outside the reserve,showing they were very similar.The community similarity coefficient of species among different habitats ranged from 0.55 to 0.81,high coefficient indicating slight difference of comprehensive environmental factors.In conclusion,Fenglin Nature Reserve had abundant butterfly resources,a healthy ecosystem,stable environment,and high protection value.