Objective We sought to determine the relationship between MP infection and secondary allergic disease and to clarify the associated mechanisms. Methods A prospective study was performed to investigate the patient’ immune status by determining serum cytokines spectrum and immunoglobulin E (IgE) levels, and to compare these indicators with sepsis patients and healthy children. Results Comparing with healthy children, children with mycoplasma pneumoniae infection Th2 cytokines, such as, IL - 4, IL - 6 and IL - 10 increased significantly. Comparing with healthy children, sepsis patients’ IL - 6 and IL - 10 levels raised significantly, but there was no significant change on IL - 4 level. Only when children infected with mycoplasma pneumoniae, the serum IgE level significantly increased. Conclusion When children with mycoplasma pneumoniae infection, the serum IgE level significantly increased, IL-4 level is the key factor for determining serum IgE levels. ThisSstudySalso shows that Th1/Th2 imbalance happened in the process of mycoplasma pneumoniae infection.