As a new form of shared mobility similar to bike-sharing, there is an increasing trend of people starting to use shared electric bicycles (SEB) for travel in China. Understanding the psychosocial factors that affect residents’ intention to use SEB is essential for the implementation of policies to develop sustainable transportation. Most research focuses on bike-sharing, while research on SEB is relatively rare. As such, this study proposes a theoretical framework based on the Theory of Planned Behavior (TPB) and the Technology Acceptance Model (TAM) to explore the mechanisms that influence the acceptance of and intention to use SEB. Drawing on this, it further addresses the moderating role of group heterogeneity and the residual effect of bike-sharing. An online survey of 313 SEB users in China was conducted in 2021. The results are constructed by structural equation modeling (SEM) and multiple-indicator multiple-cause (MIMIC) model. The results show that the research model can well explain people’s intention to use SEB. Perceived usefulness, attitude, subjective norm, and perceived behavioral control have direct positive effects on the intention to use SEB. However, there is group heterogeneity between social-economic attributes and latent variables. Moreover, satisfaction with bike-sharing could moderate the relationship between perceived usefulness and intention toward SEB. Based on the findings, some policy insights from users, government, and enterprises are proposed to guide the development of SEB.