The 20th National Congress of the Communist Party of China（CPC）clearly pointed out that achieving common prosperity for all people is the essential requirement of Chinese path to modernization, and narrowing the income gap is the key to common prosperity. The development of digital technology is a new opportunity to narrow the income gap in China. Based on the mechanisms of digital technology affecting the income gap between urban and rural residents, within rural residents and within urban residents respectively, the corresponding measurement models are constructed. Key words of "digital technology" from the government work report are collected using crawler technology to scientifically and reasonably depict the digital technology level of each province. Combined with provincial data from 2007 to 2020 in China, the effects of digital technology on China''s income gap are empirically tested. The research results show that: First, digital technology can narrow the income gap between urban and rural residents, but has no impact on the income gap within urban or rural residents. The results show some characteristics of temporal heterogeneity and spatial heterogeneity, and pass a series of robustness tests. Second, the effectiveness of digital technology needs certain external conditions as support. Digital technology plays a more significant role in narrowing the income gap between urban and rural residents in the period and region that have more developed digital infrastructure and more human capital.