Objective To analyze the prevalence of mycoplasma pneumoniae infection in children with lower respiratory tract and to provide scientific basis for clinical diagnosis and treatment.Methods Pediatric clinical data and sputum pneumonia mycoplasma DNA-PCR were collected retrospectively from January 2011 to December 2015 in the Second Affiliated Hospital of Kunming Medical University and Kunming Maternal and Child Health Hospital.Results Among 8 433 cases of sputum detection,738 cases were positive of mycoplasma pneumoniae with average detection rate of 8.8%.The detection rate were 7.9%,8.1%,7.7%,9.9% and 9.6% respectively from 2011 to 2015.The detection rates of infant group,toddler group,preschool group,and school age group were 5.6%,9.7%,17.8% and 25.1%,respectively,The detection rates of spring,summer,autumn and winter were 7.5%,6.0%,11.3% and 9.9%,respectively.Conclusions The average infection rate of mycoplasma pneumoniae in Kunming is 8.8%.The infection rate of children at school age is much higher than that of infants.Mycoplasma pneumoniae infection is more common in autumn and winter.