Background: Overweight during childhood is significantly associated with higher risk of high blood pressure (HBP) in later life. However, recognition of critical intervention period is limited. We aimed to analyze the changes in overweight risk during school-age and its relationship with HBP. Methods: Seventeen thousand eight hundred sixteen school-aged children (53.9% boys) with a mean follow-up time of 8.2 years were involved. Children's overweight was defined as body mass index Z score ≥1 and was fitted with a group-based trajectory model. The 4 trajectories were labeled as constant low, high decreasing, low rising, and constant high according to the change of overweight risk during follow-up. Population-averaged logit model and log-binomial regression models were used to analyze HBP risk. Cox proportional hazard model was used to analyze the HBP incidence among distinct groups. Results: Children with higher overweight risk generally had higher HBP risk during follow-up. However, the HBP risk in low rising group was low at baseline and increased to 3.14 (95% CI, 2.54-3.88; P<0.001) for boys and 3.23 (95% CI, 2.08-5.01; P=0.004) for girls at end point, which were comparable to the relative risk in the constant high group (4.60 [95% CI, 4.02-5.27] for boys and 5.28 [95% CI, 3.94-7.07] for girls). Conclusions: Findings of this study provide insights on patterns of overweight risks during childhood. Children with transition from normal to overweight during teen years would be high-risk in HBP incidence.