Observations for air ions concentration of mixed forest（Cinnamomum camphora× Robinia pseudoacacia× Trachycarpus fortunei）and pure forest（Elaeocarpus sylvestris、Amygdalus persica、Salix babylonica、Prunus ceraifera cv. Pissardii、magnolia grandiflora、Cedrus deodara and Cinnamomum camphora）in spring (March-May) with ITC-201A air ion monitor drawn: the air ions concentration of woodlands in Yangzhou Shugang Xifeng Ecological Park .The curve showed bimodal peaks appear in the time of 10:00 and 14:00, trough appears mostly around 12:00; there is one peak in14:00 and subsequently falls. Changes of air ions concentration in the spring monthly shows gradual upward trend in amplitude with the greatest difference between May; woodland air quality have a gradual increase in synchronization, and forest of magnolia grandiflora is the highest level. Woodland air anion concentration is negative correlated with temperature, and positive related to relative humidity.