Abstract: OBJECTIVE To analyze the value of pharyngeal swab and serum nucleic acid and antibody detection in the early diagnosis of Mycoplasma pneumoniae pneumonia（MPP） in children, so as to provide basis for clinical diagnosis and treatment. METHODS Total of 390 children in Department of Paediatrics of Hainan Women and Children Medical Center with community-acquired pneumonia（CAP） from Jan 2018 to Oct 2020 were recruited. The children with MPP were divided into the study group and the children excluded of MPP were in the control group according to the results of MP specific immunoglobulin M（MP-IgM） detection during hospitalization. The basic data and the routine laboratory indexes, the serum MP-IgM, MP deoxyribonucleic acid（MP-DNA） and pharyngeal swab MP-DNA on the day of admission between the children of the two groups were detected. RESULTS 135 children were diagnosed with MPP, accounting for 34.62% of all the children. On the day of admission, the positive rate of serum MP-IgM in the children of the study group was 50.37%（68/135）, while that soared by 100.00% after 15 days of hospitalization. On the day of admission and 2～7 days of hospitalization, the positive rates of pharyngeal swab MP-DNA and serum MP-DNA were significantly higher than that of serum MP-IgM in the study group（P＜0.017）. Receiver operating characteristic（ROC） curve analysis showed that the areas under ROC curves(AUCs^ROC) of pharyngeal swab MP-DNA, serum MP-DNA, serum MP-IgM on the day of admission in diagnosis of MPP were 0.870, 0.828 and 0.752, respectively. The sensitivity of pharyngeal swab MP-DNA was the highest with 0.830, followed by serum MP-DNA, which was 0.711. CONCLUSION The positive rate of MP-DNA in pharyngeal swab and serum of children with MPP is significantly higher than that of serum MP-IgM in the early stage of admission. The diagnositic sensitivity of MP-DNA in pharyngeal swab is extraordinary high, which can be considered to be applied in the assistance of the early etiological diagnosis of MPP.