Abstract: During June 2019 and May 2020, automatic monitoring were implemented on negative air ions (NAI) and meteorological factors in Lingjiushan Mountain National Forest Health Base, Quzhou city, Zhejiang province. The results showed that the annual average concentration of NAI was 4 475 N/cm3. It was unimodal distributed in summer with the highest average concentration and the largest variation range and the lowest in winter with no obvious daily changes. The concentration of NAI in spring and autumn showed bimodal distribution, and mean concentration had no great difference. In spring and summer, temperature and humidity had the greatest effect on NAI concentration. The contribution of meteorological factors to concentration of NAI varied in seasons, only PM2.5, air pressure and O3 showed negative relation in autumn and winter. The results revealed that the dominant meteorological factors affecting NAI concentration differed in seasons.