Objective To identify various systolic blood pressure (SBP) trajectories in Chinese boys between 7 and 18 years of age, and to explore their high blood pressure (HBP) risk in their late adolescence years. Design and settings A population-based cohort study in Guangdong, China. Participants 4541 normal tensive boys who started primary school in 2005 in Zhongshan, Guangdong were included. Outcomes Blood pressure and relevant measurements were obtained by annual physical examinations between 2005 and 2016. HBP was defined by SBP or diastolic blood pressure ≥95th percentile for children under 13, and BP ≥130/80 mm Hg for children ≥13 years old. Logit regression for panel data and log-binomial regression model was used to estimate the risk of HBP among SBP trajectory groups. Results Four distinct SBP trajectory groups via group-based trajectory modelling: low stable (13.0%), low rising (42.4%), rising (37.4%) and high rising (7.3%). The overall incidence rates of HBP during the follow-up ranged from 40.24 (95% CI 36.68 to 44.19)/1000 person-years in the low stable group to 97.08 (95% CI 94.93 to 99.27)/1000 person-years in the high rising group. Compared with children with low stable SBP, those of other SBP trajectories suffered 3.05 (95% CI 2.64 to 3.46) to 4.64 (95% CI 4.18 to 5.09) times of higher risk of HBP in their late adolescence, regardless of their age, body mass index and BP level at baseline. Conclusions Subgroups of SBP trajectories existed in Chinese boys, and are related to hypertension risk at late adolescence. Regular physical examinations could help identify those with higher risks at the beginning of pubertal growth.