The development spillovers of core cities in Guangdong-Hong Kong-Macao Greater Bay Area（GBA） have shown new bright spots since 2018，the construction of coordinated development mechanisms with non-core cities has been accelerated，infrastructure construction and interconnection has been strengthened，the process of technological and industrial spillovers from core cities to non-core cities has been accelerated significantly，and the public service sharing and ecological environment co-governance between Guangzhou and Foshan have been achieved significant results. In the bay area，the spillover scope of core cities is expanding and the spillover channels are increasing. However，there are still some factors restricting the exertion of spillover effects，such as the core cities themselves have not yet completed the transformation，the capacity of non-core cities undertaking spillovers needs to be improved，there are still many institutional barriers among cities. In the future，the GBA urgently needs to coordinate urban development with the concept of functional region. In order to further strengthen the spillover effects of core cities，the four core cities should break through the city-based thinking，accelerate urban transformation，and jointly build all-round coordinated development mechanisms with non-core cities，remove of institutional barriers to the full flow of factors.