Reduced graphene oxide (rGO) with defective structure has shown interesting magnetic properties in the frame of room temperature ferromagnetism. The origin of the magnetic moments has been explained by NMR measurements originated from the existence of defects in the samples, not from possible impurities included in the system. Recent research has revealed that the increase of heating temperature and higher content of defects may enhance magnetization in the hysteresis curves. This may attribute to the change of defect in the rGO structure influencing the magnetic ordering in the sample. In the case of mu-SR study, the relaxation rate increased whenever the sample was exfoliated, indicating that the magnetic order was probably developed. Therefore, it is important to study and correlate between the possible magnetic ordering and the presence of defect in rGO samples by means of ZF mu-SR.