The health of people with chronic diabetes mellitus (DM) complications will worsen following coronavirus disease 2019 (COVID-19) infection. This cross-sectional study compared perceptions and factors related to COVID-19 vaccination uptake between subgroups of DM inpatients with and without chronic complications in China. A multivariate logistic regression model was used for data analysis. Of the 645 participants, those without any complications reported significantly higher uptake of at least one dose of COVID-19 vaccination (43.2% versus 11.2%, p < 0.001). For people with chronic DM complications, a perception of higher risk and severer consequences of COVID-19 infection, a belief that doctors would suggest they receive COVID-19 vaccination, and a belief that relatives’ vaccination uptake would influence their own decision to receive a COVID-19 vaccination were all associated with higher COVID-19 vaccination uptake. For their counterparts without chronic complications, a perception of severer consequences of COVID-19 infection, a belief that receiving COVID-19 vaccination could reduce the risk of infection, and a belief that relatives’ vaccination uptake would influence their own decision to receive a COVID-19 vaccination were all associated with higher COVID-19 vaccination uptake. Concerns about the safety and the side effects of vaccination were negatively associated with COVID-19 vaccination uptake in both groups of DM patients. Different strategies might be applied to promote COVID-19 vaccination uptake in DM patients with and without chronic complications.