As one of the world's most prestigious city rating agencies, GaWC has published the "Global City Ranking" from 2000. GaWC will determine the status of a city in the world's urban network by examining the inter-city financial, professional, and innovative knowledge flows. GaWC divides the city into Alpha, Beta, Gamma, and Sufficiency (+/-) with its unique perspective, to show the city's position and integration in the global economy. This list is considered to be the most authoritative ranking of the world's cities in the world.

GaWC divides the world cities into four major grades - Alpha (first-tier cities), Beta (second-tier cities), Gamma (third-tier cities), and Sufficiency (a self-sufficient city, also known as a four-tier city).

GaWC ranks the world cities by using the distribution of the "Six High-level Producer Service Organizations” in major cities around the world. It mainly includes: banking, insurance, law, consulting management, advertising and accounting, focusing on the city's leading role and driving ability in global activities. GaWC's assessment of world cities does not include direct GDP and manufacturing output. In other words, the more international organizations in these industries are distributed in cities, the higher the scores of cities, and the more they are considered to be influential world cities by GaWC.

From the "Global City Ranking" released in 2018, for the Chinese cities, Hong Kong is one of the Top Three Cities, and Beijing has entered the "Top Four" for the first time. Taipei and Guangzhou are at the Alpha level. It is worth mentioning that Shenzhen has successfully entered the Alpha-level and entered the ranks of the world's first-tier cities for the first time. At the Beta level, there are 13 cities in China, including Chengdu and Hangzhou at Beta+, Tianjin, Nanjing and Wuhan at Beta level, Chongqing, Suzhou, Dalian, Xiamen, Changsha, Shenyang, Qingdao and Jinan at Beta-level.