We aimed to test the effects of pharmacist intervention on the community control of hypertension through a comparative randomized controlled trial. We recruited adult hypertensive patients with comorbidity or confusion with medication (n=636) from 2 community health centers in Zunyi, China. They were randomly and equally divided into 2 groups. Both groups received the usual care and participated in the community systematic management program of hypertension. Participants in the intervention group were given interventions from pharmacists, including a monthly review of medications, patient education, and medication adjustment advice to medical doctors over 6 months. Participants' blood pressure was assessed at baseline, 3 months, and 6 months. Participants' knowledge and medication adherence were measured using a questionnaire before and after the trial. Compared to the control group (n=298), a significantly higher percentage of participants in the intervention group (n=290) had their blood pressure under control 3 months (46.9% vs. 38.3%, P=.034) and 6 months (60.7% vs. 40.9%, P<.001) after the interventions. Difference-in-differences analyses showed that the pharmacist intervention resulted in an increase in knowledge scores by 12.55 points (P<.001), a decrease in systolic blood pressure by 6.65 mmHg (P=.001), and a decrease in diastolic blood pressure by 7.26 mmHg (P<.001) compared to the controls after adjustment for variations in potential confounding factors. The odds of participants passing the hypertension knowledge tests in the intervention group was 4.45 times those in the control group (P<.001). Similarly, it was found that the intervention group had higher odds of not needing any medication adjustments (adjusted odds ratio [AOR]=2.75, P<.001) and having their blood pressure under control (AOR=2.18, P=.002) compared to the control group. It is evident that pharmacist intervention has significant short-term effects on improving the knowledge and medication adherence of hypertensive patients, as well as timely medication adjustments from medical doctors, resulting in lowered blood pressure and an increased control rate. Further studies should explore the long-term sustainability of the effects of community pharmacist intervention.