The unbalanced allocation of healthcare resources and the underutilization of primary care facilities are the core problems that restrict the current healthcare reforms in China. In order to encourage residents to go to primary care facilities, China implemented the Hierarchical Medical System (HMS) in 2015. This study aims to evaluate the effect of HMS on health seeking behavior in China using panel data. Statistics for the study were derived from China Family Panel Studies (CFPS) 2012, 2014, 2016 and 2018, and China health and family planning statistical yearbook 2012, 2014, 2016 and 2018. We employed the difference-in-differences (DID) model with multiple periods. In total, 61,932 residents were incorporated for a final sample covered 25 provinces. The results indicated that the implementation of HMS had a significantly positive effect on the probability of urban residents going to primary care facilities for contact. However, the effect of HMS was not significant for rural residents. Basic health insurance was a significant factor for directing residents to primary care facilities. Self-assessed health, chronic disease, economic level and educational status were also found to be focal factors of health seeking behavior. In conclusion, the introduction of HMS has led to improved health seeking behavior and is worth putting more effort into. For policy makers, basic medical insurance is still an important health policy that enables systematic health seeking behavior. Initiatives to continue to expand the adjustment range of economic incentives should be adopted to promote the implementation of HMS. However, the effect of HMS in chronic disease is poor and efforts to formulate chronic disease as a breakthrough to HMS should be carried out. Moreover, the government should increase the publicity of HMS.