Water supply is related to national economy and people’s livelihood. Safe and high-quality water supply is an important source of happiness and gain for the people in the new era，and it is also a key cornerstone supporting high-quality economic and social development. The construction of the Guangdong-Hong Kong-Macao Greater Bay Area is a major national strategy. Its high-quality development vision and high-standard construction blueprint urgently require high-quality water supply security. The research focuses on the Bay Area，focuses on the basin，and faces the international community. Based on a systematic review of the current water supply situation in developed cities around the world，the current water supply pattern and water supply level of the Guangdong-Hong Kong-Macao Greater Bay Area were scientifically evaluated through investigation and analysis. Further，benchmarking international high-quality water supply standards in depth，analyzing the problems of high-quality water supply safety in the Greater Bay Area，and putting forward suggestions from the perspective of integrated water resources allocation across the river basin to improve the capacity of water supply security. The relevant results can provide a reference for the improvement of water supply facilities and service levels in the Guangdong-Hong Kong-Macao Greater Bay Area，and help promote the formation of a high-quality supply pattern of ecologically efficient water resources covering the entire Bay Area.