Objective To analyze the correlation between frailty syndrome and lower limb motor function in hospitalized elderly patients. Methods Convenience sampling method was used to select inpatients aged 65 and above from the Center of Gerontology and Geriatrics of West China Hospital, Sichuan University between December 2022 and May 2023. The FRAIL Scale, Short Physical Performance Battery (SPPB), and Timed Up and Go Test (TUGT) were used to evaluate the degree of frailty and lower limb motor function, and to explore the correlation between frailty and lower limb motor function. Results A total of 501 elderly patients were included, including 325 males (64.9%) and 176 females (35.1%); 256 cases of frailty (51.1%), 161 cases of pre-frailty (32.1%), and 84 cases of non-frailty (16.8%). The incidence of frailty in hospitalized elderly male patients was higher than that in female patients (P<0.05); The incidence of frailty in patients aged 80-99 was higher than that in patients aged 65-79 (P<0.05). The Spearman correlation analysis results showed that all dimensions of SPPB were negatively correlated with frailty (P<0.001), while TUGT was positively correlated with frailty (r=0.776, P<0.001). The results of multiple linear regression analysis showed that the worse the motor function of the lower limbs, the higher the debilitation score. Conclusions Frailty syndrome in hospitalized elderly patients is closely related to lower limb motor function. Lower limb motor function assessment can be used to predict the onset of frailty in clinical practice, and interventions to improve lower limb motor function can be used to improve the frailty of elderly patients.