The tripartite cooperation of trade unions in Guangdong, Hong Kong and Macao is a pioneering attempt to overcome the differences in social systems and an important measure to promote the integration of Hong Kong and Macao into the national development strategy. Meanwhile it has a profound impact on the development of trade unions in China. The framework construction of this system aims to serve the "one country, two systems" principle, with a reasonable distribution of participating subjects and continuous improvement of working mechanisms. Its diversifi ed promotion path includes the construction of hierarchical and coordinated hardware and software facilities, the worker cultural exchange guided by the spirit of loving the Party, loving the country and the craftsmanship, and collaborative enhancement of cross-sector social responsibilities and benefi ts. The rule coordination in the context of trade unions cooperation in the Greater Bay Area includes "seeking common ground while reserving differences" type of coordination that bridges social system differences, "equality for all" type of coordination that weakens identity differences, and "heart-to-heart communication" type of coordination that cultivates a sense of patriotism. The cooperation provides valuable insights for the integrated development of the Greater Bay Area, trade unions work, united front work, and international trade unions cooperation in the new era.