Abstract: Taking five broadleaved trees of Castanopsis fissa, Ziziphus jujube， Schia superba, Ytilaria laosensis, Alnus creastogyne as research object, the forest atmospheric ion meter of DLY3F was used to measure the content of air anion concentration at different time throughout the day, and then compared the air ion levels on five forests The results showed that, the air anion levels in five pure forest was ranged in 09×103-15×103ions/cm3, and the air quality reached to grade A. The air quality CI value of two introduced species was better than that of other three native species. Moreover, the negative air ions concentration of five pure forests could reach the peak at 8：00-10：00, but the detailed time was varied. Air anion levels of five pure forest existed significant differences in the day. However, there was no significant difference between two introduced species during the day, similar results were seen among the three native species, but there was no high correlation.