The separation of dispensary from medical practice policy is an important case of attempting a substantive approach regarding the change of decision-making in studying policy decisions and changes, which is vital question. Despite a series of policy discussions for about 40 years, the policy mix of medical practice and dispensary was continued, and was converted to the separation of dispensary from medical practice ("SDMP"), which as remarkable change. This study is trying to analyze it by policy network approach. Based on both policy actor's involvement and policy actor's exclusion, it was analyzed as to how policy decisions were affected by the characteristics of policy actor and the dynamic relationship between these. Analysis result showed that major feature of SDMP's policy network was divided into 2 groups, core and periphery, in terms of policy actor's involvement and it was confirmed that the policy decisions and changes were decided by the core of policy actors. In addition, these relationship formed dynamic relationships at the center of policy interests, which could have an impact on policy decisions. At this time, it was also confirmed the open issues in the network strengthened the dynamic relationship more, rather than a closed policy community. In conclusion, it was confirmed that the continuation and change of policy decisions regarding SDMP showed institutional characteristics of the policy network.