Objective To investigate the value of Mycoplasma pneumoniae RNA simultaneous amplification and testing(MP RNA-SAT)in the diagnosis and treatment of community acquired pneumonia(CAP) in children. Methods The clinical data of 310 children with CAP were selected for retrospective analysis,including 155 Mycoplasma pneumonia pneumonia(MPP)and 155 non-MPP,and the results of MP RNA-SAT and MP-IgM in both groups were compared. Results With the results of clinical diagnosis as reference, the specificity (97.4%)or positive predictive value (92.2%)by RNA-SAT was higher than that by IgM (72.3% and 74.4%, respectively), while the sensitivity (30.3%)or negative predictive value (58.3%)was lower than that by IgM (80.6% and 78.9%, respectively).The difference was statistically significant (P<0.05). Age>3 years, no macrolide treatment before testing, or choosing bronchoalveolar lavage fluid as testing samples, that can improve the detection rate of RNA-SAT(P<0.05). Conclusion RNA-SAT may specifically identify active infection of MP, and the combined use of RNA-SAT and IgM test may more quickly and accurately diagnose infection of MP.It has high value for the diagnosis and treatment of community acquired pneumonia in children. RNA-SAT should be performed before the application of macrolide treatment as early as possible. If necessary, bronchoalveolar lavage fluid could be chosen as testing samples to improve the detection rate of RNA-SAT.