During the 15th Five-Year Plan period, China is committed to promoting high-quality development, with a focus on strengthening the real economy and advancing digitalization, green transformation, and integration. Consequently, the integration of the digital economy and the real economy has become a key driver of urban innovation vitality. Based on an analysis of panel data of Chinese cities from 2008 to 2024, this study empirically investigates the mechanism through which digital-real economy integration enhances urban innovation vitality. The findings indicate that the deep integration of the digital and real economies significantly improves urban innovation vitality. This conclusion remains robust after a series of robustness tests. Mechanism analysis reveals that digital-real economy integration enhances urban innovation vitality by optimizing factor inputs, fostering new industrial forms, and improving new digital infrastructure. Spatial effect analysis indicates that digital-real economy integration positively promotes the innovation vitality of surrounding cities. Heterogeneity analysis reveals the following patterns. The positive impact of digital-real economy integration on urban innovation vitality is significantly stronger in central and eastern regions and core cities than in other regions. This positive effect is even more pronounced in cities of South China, Central China, and Northeast China compared to other areas. However, a negative effect is observed in East China and North China. These findings suggest that the depth of integration between the digital economy and the real economy is the key to enhancing urban innovation vitality. Finally, this study proposes policy recommendations to promote the deep integration of the digital and real economies.