Objective To investigate the expression and significance of interkeulin 10 (IL-10)in children patients with mycoplasma pneumoniae pneumonia(MP). Methods Twenty-six children patients with MP( MP group)and20 health control( contrl group)were sequentially enrolled in this study. The production of IL-10 mRNA was measured by fluorescent quantitative polymerase chain reaction. Results Expression of IL-10 mRNA in MP group (33 893.22±5 207.60) copy/μg was significantly lower than that in control group(59 341.92 ±6 712.98) copy/μg(t = - 14. 49, P ＜ 0. 01 ). Expression of IL-10 mRNA in heavy degree MP group was significantly lower than that of mild degree MP group ( t= - 2. 20, P ＜ 0. 05 ). Conclusion The expression of IL-10 was low, and played an important role in the development of patients with MP.