In October 2021，the Hong Kong SAR Government proposed the establishment of the “Hongkong Northern Metropolitan Area” in Yuen Long District and Northern District to create Hongkong’s second economic engine. Shenzhen is adjacent to the Northern Metropolitan Area and is an important component of the “Twin Cities and Three Circles” proposed in the Northern Metropolitan Area Development Strategy，and participation in the Northern Metropolitan Area will provide a demonstration for closer cooperation between the Mainland and Hongkong and Macao. The thesis holds the view that the construction of the northern metropolitan area will face challenges from four aspects，such as the obstruction by vested interests in the south，conflicts on environmental protection，repeated pandemics，and direct competition with Shenzhen. It is suggested that Shenzhen take industrial cooperation as a breakthrough to strengthen transportation connectivity and customs clearance facilities between the two places，and actively participate in the construction of major infrastructure in Hongkong，jointly protect the environment，and help the deep integration of the Guangdong-Hongkong-Macao Greater Bay Area.