The prevalence of food allergy (FA) has increased worldwide. In China, the prevalence of FA in infants and school-aged children is well known, but the prevalence in preschool children is unknown. A total of 4151 preschool children aged 3 to 6 years in urban Wenzhou, China, were recruited for this cross-sectional study. Their parents completed a preliminary screening questionnaire, and a detailed FA questionnaire was given to parents whose children had suspected FA according to the preliminary screening. According to the results of the detailed FA questionnaires, some children underwent a skin prick test (SPT) and specific IgE (sIgE) measurement. Children with abnormal SPT and/or sIgE results who did not meet the diagnostic criteria and those with negative SPT and sIgE results whose histories strongly supported FA underwent an oral food challenge (OFC). Of the 4151 children's parents who completed the surveys, 534 (12.86%) indicated a positive medical history of FA. Among the 40 children who underwent an OFC, 24 were positive. According to SPT and sIgE measurements, 11 children were diagnosed with FA. The prevalence of FA was at least 0.84%; children who dropped out during the study were considered FA-negative. Among the 35 children with FA, the most common allergic manifestation was skin symptoms. The most common allergic foods were egg, fish and shrimp. The parent-reported rate of FA in preschool children in urban Wenzhou was 12.86%. The prevalence of FA was at least 0.84%. Among all cases, the most common allergic food was eggs, and the most common allergic manifestation was skin symptoms. NCT03974555, registered on 30 May 2019 (www.clinicaltrials.gov).