Injurious falls pose a significant threat to the safety of stroke patients, particularly among older adults. While the influence of activities of daily living (ADL) on falls is acknowledged, the precise connection between ADL ability and fall-related injuries in older stroke patients undergoing rehabilitation, particularly those with varying mobility levels, remains unclear. This multicenter cross-sectional study in China recruited 741 stroke patients aged 65 years and above, categorized into bedridden, domestic, and community groups based on their mobility levels using the Longshi Scale. ADL ability was assessed using the Barthel Index. Logistic regression models, generalized additive models, smoothed curve-fitting, and threshold effect analysis were employed to explore the relationship between ADL ability and injurious falls across the three mobility groups. Results revealed an inverted U-shaped relationship between ADL ability and injurious falls among patients in the domestic group (p = 0.011). Below the inflection point of 35 on the Barthel Index, the likelihood of injurious falls increased by 14% with each unit increase in ADL ability (OR = 1.14, 95% CI 1.010-1.29, p = 0.0331), while above the inflection point, it decreased by 3% per unit increase (OR = 0.97, 95% CI 0.95-0.99, p = 0.0013). However, no significant association between ADL ability and injurious falls was observed in either the bedridden or community groups (p > 0.05). These findings suggest that only older stroke patients capable of engaging in activities at home demonstrate a correlation between ADL ability and injurious falls. The identified inverted U-shaped relationship may aid in identifying fall injury risk in this population.