It is important to establish social stability risk appraisal system to construct harmonious society.Its establishment shall be human-oriented，its system design shall include guiding principle，basic rules，participants，fields，way and procedure of participation，and guarantee measures，and its content shall cover the legality，rationality，promulgating conditions，and relevant environment of important issues，social safety，and other important issues that will appear during implementation and affect social stability.There also exist difficulty questions that to be dealt with，including how to increase efficiency of public participation and decision making and to prevent formalism during this process，how to evaluate the scientificalness of the appraisal results，and how to ensure the responsibility backtracking investigation system to be fully executed.