Abstract: With the integration of the aging society and the digital society, researches on the digital life of senior citizens have attracted attention from many countries and fields. This article used open-ended interviews and grounded theory to collect and analyze data and took smart phones as an example to conduct research on the digital life of senior citizens. The authors selected 7 representative locations in a provincial capital city in central China to conduct interviews and analyzed the senior citizens’ behaviors in using smartphones and the factors affecting them, with the help of the grounded theory three-level coding analysis method. While revealing the status of senior citizens’ use of smartphones, the authors identified the influencing factors such as personal capital, interpersonal network, social environment, and equipment performance. At the same time, these factors influenced each other. Based on the above conclusions and in view of the national strategy of active aging, it proposed a solution to improve the digital life of senior citizens.