Abstract: At present, the somatic function assessment of the elderly mostly depends on the doctor's observation and the scale evaluation, and there isn't the objective and quantitative assessment criteria. In this paper, we design and construct a digital system for the geriatric somatic function assessment, which is based on digital ground, inertial unit, mobile terminal and PC terminal. The gait and balance parameters of the elderly were obtained by the Time Up and Go test and five postures test. Based on the linear regression model of gait and balance parameters, the system was used to evaluate the somatic function of the elderly. The experimental results show that the system not only can accurately distinguish elderly between fall and non-fall, but also has a high correlation between the score of the system and the score of clinical geriatric physical function scale.