Objective To analyze the effect of low-dose methylprednone sodium succinate combined with erythromycin in the treatment of Mycoplasma pneumoniae infection with elevated lactate dehydrogenase(LDH)in children.Methods Children with Mycoplasma pneumoniae pneumonia(MPP)complicated with elevated LDH were divided into control group and treatment group by random number table method.The control group was given erythromycin treatment,and the treatment group was given low-dose methylprednisolone sodium succinate combined with erythromycin treatment.Clinical efficacy and clinical symptom disappearance time were recorded in both groups.Pulmonary X-ray signs,immune function[T cell subsets(CD4+,CD8+,CD4+/CD8+)],immunoglobulin(Ig)A,IgM and serum LDH were compared between the two groups before and after treatment,and the adverse drug reactions of treatment were observed.Results There were 51 cases in control group and 51 cases in treatment group.The total effective rate in treatment group was 96.00％,which was significantly higher than 81.63％in control group(P＜0.05).The fever abatement times in treatment group and control group were(4.22±0.87)and(5.46±0.98)d;cough disappearance times were(6.31±0.98)and(7.49±1.10)d;disappearance times of pulmonary rales were(7.36±1.14)and(8.61±1.23)d,all with significant difference(all P＜0.05).After treatment,the patchy infiltrating shadow sign rates in treatment group and control group were 2.00％and 16.33％;the bronchial wall thickening sign rates were 4.00％and 18.37％,all with significant difference(all P＜0.05).After treatment,IgA levels in treatment group and control group were(0.55±0.11)and(0.68±0.12)g·L-1;IgM levels were(0.90±0.19)and(1.18±0.21)g·L-1;LDH levels were(229.45±10.30)and(240.18±11.17)U·L-1,all with significant difference(all P＜0.05).The total incidence of adverse drug reactions in treatment group and control group were 6.00％and 4.08％respectively,without significant difference(P＞0.05).Conclusion Erythromycin combined with low-dose methylprednone in systemic treatment of children with MPP and elevated LDH has a significant efficacy,and it can promote the reductions of inflammation and immune disorders and accelerate the disease outcomes,and it is safe and reliable.