This study aimed to evaluate the impact of updated pediatric hypertension (HTN) criteria (the 2017 AAP Guidelines) on prevalence estimates of HTN and prehypertension among Chinese children compared to the 2004 Fourth Report. A total of 2093 children aged 7-15 years from five schools in Tianjin, China were selected using a multistage random cluster sampling method. The prevalence of HTN per the 2017 AAP Guidelines (10.1%) was significantly higher than that per the Fourth Report (6.6%), whereas the prevalence of prehypertension per the 2017 AAP Guidelines (6.3%) was significantly lower than that per the Fourth Report (8.8%). From the 2004 Fourth Report to the 2017 AAP Guidelines, a total of 117 (5.6%) children were reclassified to have higher blood pressure. The two criteria had better consistency in the diagnosis of systolic abnormalities than in the diagnosis of diastolic abnormalities. The updated definitions for pediatric HTN have a substantive impact on the prevalence estimation among Chinese children, especially among boys, overweight children, and older children.