Objective To explore the correlation between levels of serum B-type natriuretic peptide (BNP), lactate dehydrogenase (LDH) and homocysteine (Hcy) and myocardial damage in children with Mycoplasma pneumonia (MP). Methods The data of 113 children with MP in the hospital were retrospectively analyzed and the patients were divided into non-myocardial damage group (n=77) and myocardial damage group (n=36) according to whether myocardial damage occurred. The general data and serum BNP, LDH and Hcy levels between the two groups and levels of serum BNP, LDH and Hcy among children with different degrees of myocardial damage were compared. Pearon correlation analysis was used to analyze the relationship of serum BNP, LDH and Hcy levels with myocardial damage indicators ［creatine kinase (CK), creatine kinase isoenzyme (CK-MB), cardiac troponin T (cTnT), α-hydroxybutyrate dehydrogenase (α-HBDH)］. Multivariate Logistic regression analysis was applied to analyze the related factors affecting myocardial damage in children with MP. Results The fever duration, disease severity, MP antibody titer, PLT and serum CRP, Scr, CK, CK-MB, cTnT, α-HBDH, BNP, LDH and Hcy levels in myocardial damage group were significantly higher than those in non-myocardial damage group (P＜0.05). There were no statistical differences in gender, age, infection site, WBC, RBC and ALB between the two groups (P＞0.05). The levels of serum BNP, LDH and Hcy were significantly lower in mild group than those in moderate group and severe group, and the above levels in moderate group were significantly lower than those in severe group (P＜0.05). Pearson correlation analysis showed that serum BNP, LDH and Hcy levels in children with MP were significantly positively correlated with CK, CK-MB, cTnT and α-HBDH (P＜0.05). Multivariate Logistic regression analysis showed that duration of fever, severity of disease, serum BNP, LDH and Hcy were risk factors for myocardial damage in children with MP (P＜0.05). Conclusion Serum BNP, LDH and Hcy levels in children with MP are significantly correlated with myocardial damage, and are risk factors for occurrence of myocardial damage