Abstract: Ants are important in the ecosystem, and their species diversity can indicate the changes of the environment. In order to understand the diversity of ants in plantations and the influence of different sampling periods on the diversity survey results, the ants in plantations in Gucheng campus of Dali University were collected by the Pitfall-trap method from September 2017 to August 2018. The diversity of ants in plantations was analyzed, and the dynamic changes of annual cycle and the changes of ants’ diversity in different months were analyzed. A total of 7692 ants were collected, belonging to 4 subfamilies, 17 genera and 31 species （including 5 undetermined species）, and the Shannon-Wiener diversity index was H=2.153 ± 0.413, which was different from the results of ants in Cangshan area. In each month, the number of ants’ species and individuals in plantations showed a single-peak seasonal dynamic pattern, which first increased and then decreased. In June and July, the abundance and diversity of ants were higher than those in other months, so it was suggested to monitor the diversity of ants in this period in the future. In this study, it was found that the plantations in the campus has good protection for the ants’ diversity in the region, and the future monitoring of ants’ diversity can be carried out in the months with higher diversity to increase the representativeness of sampling and the comparability of different regions.