This paper focuses on island tourism，and analyzes and compares the two typical cases of Wanshan Islands in Zhuhai city and Shangxiachuan Island in Jiangmen city by means of the multi-case comparison method，so as to conduct an overall study and judgment on the development status of island tourism in the Greater Bay Area of Guangdong，Hong Kong and Macao. In general，at present，the importance of island tourism in the development of Marine industry in Guangdong-Hong Kong-Macao Greater Bay Area is far from enough，and the driving effect of island tourism on the society，economy and culture of Guangdong-Hong Kong-Macao Greater Bay Area is actually relatively weak.