Objective: To observe the clinical effects of vitamin D ₂ in adjuvant treatment of community acquired pneumonia (CAP) in children. Methods: 120 CAP children were randomly divided into observation group (60 cases) and control group(60 cases). The children in control group were treated with conventional therapy; on this basis, the children in observation group were also given intramuscular injection of Vitamin D ₂. After 7d treatment, the total effective rate, remission time of infection symptoms (cough, lung rale, fever abatement) and hospital stay of children in 2 groups were compared. And ELISA was used to detect the serum 25-(OH)D ₃ and inflammatory factor (TNF-α, IL-1β, IL-6, IL-8) content of all the children before and after treatment. Results: Compared with children in the control group, after treatment, the remission time of infection symptoms (cough, lung rale, fever abatement) and hospital stay of observation group significantly shortened, the total effective rate and serum 25-(OH)D ₃ significantly increased, the serum inflammatory factor (TNF-α, IL-1β, IL-6, IL-8) content significantly decreased (P<0.05, P<0.01). Conclusions: Vitamin D ₂ has adjuvant therapeutic effects on CAP children, and the mechanisms may be related to reducing the content of inflammatory factors.