A motion capture system includes a motion sensor having a flexible body and a fiber bragg gratings (FBG) sensor inserted into the body, a fixture configured to fix the motion sensor to a human body of a user, a light source configured to irradiate light to the motion sensor, and a measurer configured to analyze a reflected light output from the motion sensor, wherein the FBG sensor includes an optical fiber extending along a longitudinal direction of the body and a sensing unit formed in a partial region of the optical fiber and having a plurality of gratings, and wherein a change of a wavelength spectrum of the reflected light, caused by the change of an interval of the gratings due to a motion of the user, is detected to measure a motion state of the user.