Objective To explore the clinical significance of changes on serum IL-2, IL-10, IL-18 and D-D levels after treatment in pediatric patients with mycoplasma pneumonia. Methods Serum IL-2 (with RIA), IL-2 (with RIA) , serum IL-10, IL-18 (with ELISA) , serum D-D (with immunoturhidimetry) levels were determined in 32 patients with pediatric mycoplasma pneumonia patients and 35 normal healthy children. Results Before treatment, serum IL-2 level showed significantly lower than that in controls (P <0.01). but serum IL-10,IL-18 and D-D levels were significantly higher than those in contrals(P<0.01). After treatment for 2 weeks the levels in patients manifested no more different from those in controls(P>0.05). Serum IL-2 level was negative correlated with serum IL-10, IL-18 and D-Dlevels(r=-0.4806, -0.5014, -0.5988, P<0.01).Conclusion The cytokines IL-2, IL-10, IL-18 and D-D might participate in the whole process of mycoplaama infection, monitoring the changes of these cytokines could be helpful to the diagnosis, treatment and prognosis of the diseases and provides certain clinical values.