A comparative study of crystallographic changes of the graphite anodes mixed with SiO x (in short, graphite-SiO x ) to the pristine graphite during the lithium insertion and extraction under a half-cell condition is conducted by using in situ XRD for the first time. The structural changes of the graphite-SiO x anodes are relatively quantified from the time-dependent alteration in a and c lattice constants of their contained graphite during the charge and discharge. The results clearly confirm that Li+ ions are inserted in the SiO x domain prior to graphite during the charge, and the delithiation takes place later in SiO x during the discharge consistently. Via this in situ XRD study, the electrochemical effect of the amount of silicon active materials in the graphite-SiO x is also monitored up to the 160% increase of the capacity.