Based on panel data from 2010 to 2019, this study examines the relationship between defense science and technology innovation and high‐quality economic development at the provincial level in China. Using the gray correlation analysis method of panel data and an evaluation index system of high‐quality economic development, we calculate the gray correlation coefficient and decompose its time‐series gray correlation degree and cross‐sectional. Our findings indicate that the correlation between defense science and technology innovation and high‐quality economic development in China is generally stable during 2010–2019. However, Beijing stands out as an exception with a correlation coefficient of less than 0.5. Furthermore, there is regional gray correlation heterogeneity with the smallest correlation degree found in the eastern region and the largest in the northeast region. Based on our results, we propose three countermeasure suggestions: first, to balance national defense construction and economic construction; second, to optimize national defense science and technology strategy according to local conditions; and third, to effectively utilize industrial structure advantages. In summary, our study contributes to the literature by highlighting the relationship between defense science and technology innovation and high‐quality economic development in China. Our findings provide implications for policymakers and practitioners to make informed decisions in achieving sustainable and high‐quality economic development.