Trade cooperation plays an important role in promoting regional economic cooperation and regional integration. In order to promote the construction of the Guangdong-Hong Kong-Macao Greater Bay Area (GHMB) and enhance its position in the global trade network, it is urgent to clarify the trade relationship in GHMB and promote the coordinated development of trade among the three component tariff zones. Under this background, based on the data from International Trade Centre (ITC) and regional statistical yearbooks, this paper analyzes the evolution of trade competition and cooperation in GHMB, and tries to find a way to foster regional integration of GHMB. The results show that: (1) In the last decades, GHMB has expanded its overall trade scale and raised its status in the global trade network, which provide itself the potential to develop into a world-class bay area. However, its financial market still remains to be optimized thoroughly. (2) With the continuous strengthening of Guangdong's trade links with the world, Guangdong has gradually overtaken Hong Kong in trade volume. Thus, strong potential competition between Guangdong and Hong Kong’s re-export-led trade has arisen in terms of trade space and trade commodity structure. Besides, potential competition also exists between Hong Kong and Macao in re-export trade. (3) The three component tariff regions in GHMB have varied advantages in different parts of trade competition. Specifically, Guangdong shows a competitive advantage in trade at the level of agglomeration, Hong Kong has a significant advantage in the level of investment liberalization, and Macao has a relatively limited scale in most trade competitive indicators. (4) The trade links between Guangdong, Hong Kong, and Macao have been continuously strengthened. Trade cooperation pattern in GHMB still retains some characteristics of its earlier stages, as the stores in the front and factories at the back cooperation model. However, the proportion of processing trade in total trade volume has been declining. (5) To promote internal trade cooperation in GHMB, it is necessary to make full use of each other’s trading advantages, foster the cooperation and coordinated development of commodity trade, expand the trade spaces of the three component tariff zones, and promote closer cooperation in service trade.