Abstract:As bridges and links between the Party and the masses, mass organizations play a key and unique role in promoting social construction. Since the 18th CPC National Congress, the CPC Central Committee with Comrade Xi Jinping as its core has attached great importance to social construction. This study takes trade union organizations as an example to analyze and point out that the participation of mass organizations in social construction is conducive to realizing the Party's leadership in promoting social construction, implementing the people-centered philosophy of social construction, and implementing the national strategy of governing China based on the rule of law and improving the level of legal institutionalization of social construction. The main tasks of mass organizations in participating in social construction include playing a complementary role in ensuring and improving people's livelihoods, promoting common prosperity, playing a coordinating role in safeguarding rights and resolving conflicts through consultation, and promoting social fairness and justice, etc. Thus, the study suggests the following measures be taken: improve the ability of mass organizations in participating in social construction through reform and innovation; enhance initiative and timeliness by strengthening the role of safeguarding workers' rights in participation; accelerate the construction of an intelligent trade union and innovate the ways of participation; keep within the limits of trade unions participation by striving to maintain political security in labor fi elds; and enhance the participatory forces by strengthening the construction of grassroots trade unions.