Introduction: Gait speed and grip strength are objective indicators of body function that are easily obtainable and cost short time in measurement. The International Myeloma Working Group (IMWG) recommends using frailty assessment tools to assess the level of frailty in patients and providing individualized treatment based on frailty, disease characteristics, and patient preferences. The consistency among the assessment results measured by gait speed and grip strength as well as IMWG has been demonstrated in previous studies, however, there are few studies reporting the significance of gait speed and grip strength in predicting the prognosis of patients with multiple myeloma. Methods: Fifty eight elderly patients with MM who were ineligible for transplantation were included to analyze the differences in AE, early mortality, and discontinuation rates among different frailty groups assessed using gait speed, grip strength, and IMWG-FI, respectively. A univariate comparison was conducted to test the effects of gait speed, grip strength, IMWG-FI, MRP, IFM, DXA, IL-6, ADL, IADL, CCI, age, ISS staging, and treatment regimen on OS. This was followed by a multivariate Cox regression analysis. Results: 1.Comparison of nonhematological AEs of above Grade3: there were statistical differences in groups with different gait speeds, grip strength, and IMWG-FI; Comparison of hematological AEs of above Grade 3: there were differences among different grip strength groups; Comparison of discontinuation rates: there were differences among groups with different gait speeds and IMWG-FI, while there was no difference between grip strength groups; Comparison of 3-month, 6-month, and 12-month early mortality: no differences were observed except for differences in grip strength groups at 3 months. 2. There were statistical differences in OS among different gait speed, grip strength, IMWG-FI, MRP, DXA, IL-6, ADL, and age groups. Multivariate Cox regression analysis was conducted by incorporating age, gait speed, grip strength, ADL, and IL-6, and gait speed was identified as a significant influential factor on OS. Conclusions: The study demonstrated that gait speed is predictive of OS in MM patients and is an independent prognostic factor, it also can predict the incidenct of AE events and treatment discontinuation. Therefore, gait speed reflects not only the functional status but also the frailty condition of patients, it is a promising indicator of frailty assessment. Additionally, for elderly MM patients, many of them are suffering from bone diseases that affect gait speed, and grip strength can be an effective supplement to gait speed.