Under the new development pattern，the high-tech industry has become an important force to promote the transformation and upgrading of modern urban economy and high-quality development. Therefore，systematic research on how to better enhance international competitiveness has also become a hot issue in current academic research. Based on the situation of the construction of the Guangdong-Hong Kong-Macao Greater Bay Area，this study takes Guangzhou and Shenzhen as examples，and combines the development status and reality of their high-tech industries to compare，analyze and evaluate the international competitiveness of their high-tech industries. This paper further finds out the bottlenecks and shortcomings of the high-quality development of high-tech industries in Guangdong-Hong Kong-Macao Greater Bay Area cities，and based on this，gives suggestions on how to better support the competitiveness upgrade of high-tech industries in Guangdong-Hong Kong-Macao Greater Bay Area cities in the next stage.