Objective To investigate the correlation between vitamin A (VA) levels and the severity of community-acquired pneumonia (CAP) and mycoplasma pneumoniae (MP) infection in children, thus to provide reference for the prevention and treatment of CAP in children and the assessment of the disease. Methods A total of 155 children≤5 years old, who were hospitalized due to CAP, were randomly selected as study subjects. Patients were divided into groups according to the severity of the disease and the presence or absence of MP infection, and the serum VA levels were compared between the groups. Results The average VA level of 155 children with CAP was 0.19±0.06mg/L. The VA level in the mild pneumonia group was higher than that in the severe pneumonia group, the detection rates of clinical type VA deficiency (CVAD) and subclinical type VA deficiency (SVAD) in the severe pneumonia group were significantly higher than that in the mild pneumonia group, and the detection rates of marginal type VA deficiency (MVAD) in the mild pneumonia group were higher than that in the severe pneumonia group, with statistically significant differences (P<0.05). The VA level of the MP negative group was higher than that of the MP positive group, the detection rate of SVAD in the MP positive group was higher than that of the MP negative group, and the detection rate of MVAD in the MP negative group was higher than that of the MP positive group, with statistically significant differences (P<0.05). VA levels were associated with CAP severity and MP infection. Conclusion The VA level is related to the severity of CAP in children, and MP infection will further reduce the VA level in children with CAP.