Objectives. There is a need to assess the 2009 new healthcare reform in China on hypertension prevention. It helps to control from the perspectives of multisectoral participation, government responsibility assignment, performance assessment, and service delivery. Design. Interrupted time-series study. Setting. 31 provinces in mainland China. Primary and Secondary Outcome Measures. Based on the content analysis of publicly available policy documents from 31 provinces regarding hypertension prevention and control, we analyzed the changes brought by the 2009 new healthcare reform through four quantitative indicators, including multisector participation (MP), main department responsibility coverage (MDRC), primary department assessment indicator coverage (MDAIC), and service type coverage (STC). We compared the changing trends of four indicators before and after 2009. Results. Nationally, MP, MDRC, and STC grew rapidly and increased to 88.9%, 96.4%, and 77.8%, respectively, in 2017, higher than MDAIC (36.9%). This growth was accelerated by the new healthcare reform, with the highest acceleration in MP (β3 = 6.345,
p
<
0.001
), followed by MDRC (β3 = 3.829,
p
<
0.01
), STC (β3 = 3.799,
p
<
0.001
), and MDAIC (β3 = 3.585,
p
<
0.001
). The MP and MDRC trend changes were higher in the central and western regions than in the east after the reform. Conclusions. Our research showed that the new healthcare reform had a positive effect in promoting multisectoral participation in preventing and controlling hypertension in China, improving the responsibility mechanism, and expanding the types of services provided. The government should lead the coordination and implementation of multidepartmental responsibilities and mobilize nonhealth departments to continuously participate in the prevention and control of chronic diseases by improving incentive and evaluation mechanisms.