The present invention provides a system and method for evaluating Range of Motion of a subject. An aspect of the present invention proposes a system for evaluating Range of Motion of a subject, comprising markers attached to at least two joints of a body part of the subject respectively; an image capturing device for capturing images of the markers when the subject is doing an exercise with the body part attached with the at least two markers; and an evaluating device communicated with the image capturing device, wherein the evaluating device includes a determining unit configured to determine whether the exercise done by the subject is valid for the evaluation of Range of Motion of the body part of the subject, and a calculating unit configured to, if the exercise is valid, calculate the parameters related to Range of Motion of the body part of the subject according to the images related to the valid exercise. Thus, the work load of clinicians can be greatly reduced during the process of evaluating Range of Motion, and the accuracy of the evaluation of Range of Motion can be improved as well.