In recent years, the evaluation of regional innovation capability has become a hot issue in academia and industry. On the basis of existing studies, the paper puts forward the concept and measure indicators of Industrial Knowledge Diversity, and apply them to the evaluation of regional innovation capability, with a view to providing some useful attempts for relevant researches and practice works. Taking the data of 9 cities in Fujian Province as an example, the empirical analysis shows that there is a positive correlation between regional industrial knowledge diversity and GDP, which indicates that the idea of evaluating regional innovation ability based on industrial knowledge diversity has certain theoretical value and practical significance.