To implement the Opinions of the General Office of the CPC Central Committee and the General Office of the State Council on Innovating Approaches to the Mass Work and Solving Prominent Problems in Petitions，the Bureau of Petitions of Sichuan Province have established a third-party assessment platform to enable social forces to participate in the assessment of matters relating to petitions，thereby effectively solving difficult and long-pending petition cases. This report analyzes the function and role of this work mechanism from the perspectives of the necessity and feasibility of the participation by social forces in the mechanism. On the basis of empirical investigation，the report focuses on the Sichuan practice，namely how to introduce third party assessment into the work of dealing with petitions and，in light of the Sichuan experience，puts forward suggestions on how to carry out empirical studies on the establishment and improvement of third-party assessment of the system of petitions from the perspectives of cognitive mechanism，main body mechanism，procedure mechanism，content mechanism，safeguarding mechanism，and adjustment and improvement mechanism.