Abstract: The ecological consequences of the changes in ecosystem functions caused by land use change have attracted more attention in recent years. However, less study has focused on the relationship between biodiversity and ecosystem function. Agroforest ecosystem is the combination of agriculture and forestry for management purposes. As an important model, agroforestry has vital ecological benefits for land use substantial development. Agroforestry has been considered to support more species survival and higher biodiversity. Lac insects (Kerria spp.) as well as their excrement are important resource insects widely used in many fields including food, medicine and military industry. Lac-corn agroforestry ecosystem is popular pattern of lac production in mountain areas of Southwest China where lac production accounts for a good fraction of the income of farmers’ households. However, there is less research on the functional groups of arthropods in lac-corn agroforestry. Ants (Hymenoptera: Formicidae) are widely distributed in many terrestrial ecosystems. They can be used as indicator for evaluating environmental changes and ecosystem health because they are sensitive to disturbances in important functions of ecosystem. Studies have shown that functional groups constitute a useful method of predicting the response of ant communities to disturbances and environmental changes. This study determined the effects of lac-corn agroforest ecosystem on the diversity and functional groups of ground-dwelling ant communities and the role of lac-corn agroforestry ecosystem in ant diversity and ecosystem function protection. A research was conducted using pitfall traps on ground-dwelling ant communities in lac plantation, lac-corn agroforest ecosystem and cornfield in Lüchun County. A total of 11 781 individual ants were collected, belonging to 78 species, 37 genera and 7 sub-families. Lac-corn agroforest ecosystem had higher species and rare species numbers of ground-dwelling ant communities. In lac-corn agroforest ecosystem, the numbers species and rare species increased by 41% and 85%, respectively, compared with cornfield. Ant abundance in lac-corn agroforest ecosystem was significantly higher than that in lac plantation and cornfield. Ant abundance, ACE of ant in lac-corn agroforest ecosystem and lac plantation were significantly higher those of cornfield. Ant community structure of lac-corn agroforest ecosystem was similar to that of lac plantation, but dissimilar compared with cornfield. There were differences of species compositions and indicator species of the three sites. Paratrechina vividula and Pheidole yeensis were dominant species in cornfield, Aphaenogaster beccarii in lac plantation, and then Monomorium chinensis, M. orientale, Crematogaster rogenhoferi, Polyrhachis proxima and Cardiocondyla wroughtonii in lac-corn agroforest ecosystem were dominant species. Iridomyrmex anceps and P. yeensis were indicator species for cornfield, Dolichoderus incises, Lepisiota xichangensis and M. chinensis were indicator species for lac-corn agroforest ecosystem, and then A. feae, C. ferrarii, Tetramorium aptum, A. beccarii, and Pseudolasius silvestrii were indicator species for lac plantation. The proportions of different functional groups of ants in lac-corn agroforest ecosystem were in between lac plantation and cornfield. Species richness, abundance and proportions of Opportunists, Subordinate Camponotini, Cryptic Species and Climate Specialists in lac-corn agroforest ecosystem were higher than those in cornfield. Honeydew secretion by lac insects increased ant species richness and abundance in lac-corn agroforest ecosystem and lac plantation. Lac plantation and lac-corn agroforestry with more complex habitat supported more arthropods survival. Lac-corn agroforest ecosystem limited biodiversity loss caused by disturbances. It had positive effects on the protection of ground-dwelling ants and was a better sustainable development model for balancing the contradiction between environmental protection and economic development.