In order to reveal the effects of population of Kerria yunnanensis on diversity of ground-dwelling ant, investigation of ground-dwelling ant diversity in 4 plots, with infestation rate of Kerria yunnanensis on host plant branches being 60%, 30%, 10% and 0%, respectively, was carried out by pitfall trapping in lac plantation in Yayi Town, Mojiang County, Yunnan Province of China. 1) Species composition and relative abundance: 1136 ant individuals were collected in the plot Ⅰ, representing 26 species, the common species were Pheidole spathifera, Pheidole yeensis and Aphaenogaster beccarii. 984 ant individuals were collected in the plot Ⅱ, representing 24 species, the common species were Monomorium chinensis, P. spathifera, P. yeensis and Pheidole pieli. 607 ant individuals were collected in the plot Ⅲ, representing 24 species, the common species were Crematogaster macaoensis, M. chinensis and P. spathifera. 419 ant individuals were collected in the plot Ⅳ, representing 26 species, the common species were Odontoponera transversa, M. chinensis and P. spathifera. 2) ant diversity: relative abundance was in the order as Ⅰ＞Ⅱ＞Ⅲ＞Ⅳ. Honeydew can increase number of individuals and relative abundance, but none significant effects on species richness. 3)Community similarity: Plots with lac insects hosting were different from the plot without lac insects hosting, there were some differences of community structure between each plot with different level of lac insects infestiation. 4)Indicator species: Anoplolepis gracilipes and Tetramorium walshi were the indicator species of plot Ⅰ, Technomyrmex bicolor was the indicator species of plot Ⅲ, none indicator species in plot Ⅱ and plot Ⅳwas found. Lac population maintained higher ground-dwelling ant community diversity by honeydew resources, and changed the ground-dwelling ant community structure.