The medical security system in China is more emphasis on the rights and obligations of the government and medical insurance agencies. However, from the background of the social management to the social governance and the perspective of the right structure of justice, improvement of the public participation in medical security system is necessary. We elaborate the construction reason, framework, support and other aspects of public participation in medical security system. By analyzing right?-obligation structure and the design of logical structure, the public should be substantially involved in the medical security. We propose views of idea transfer from the right of participation to the right to participate, from the right of expression to the right to vote, and from the right of supervision to the right of supervision and administration, in order to better protect the health of citizens.