The renewal of old communities (OCR) is a crucial component of China's urban renewal strategy. However, the huge funding gap, coupled with the unwillingness of enterprises to participate, has impeded the sustainable development of OCR in China. This issue has become a major practical challenge for the government. This study employed the modified theory of planned behavior (M-TPB) to examine enterprise behavior, focusing on how internal capabilities and external conditions influence their participation. Data was collected from 261 questionnaire surveys, and structured equation modeling was used to analyze the data. Further in-depth interviews were conducted to explain and validate the results from the SEM. The findings illustrate that: (1) the M-TPB offers a more detailed and nuanced explanation of the mechanisms influencing participation behavior; (2) the attitude towards participation is an important factor in shaping the intention to participate; (3) there is a significant negative correlation between perceived behavioral control, which is based on external conditions, and the participation intention; and (4) different types of enterprises show differences in attitude and perceived behavioral control. These findings provide new insights and perspectives on the OCR dilemma in China, highlighting some important practical implications for fostering various forms of enterprise participation in OCR projects.