Considering the loss of fiber delay line,a new theoretical analytical model for the dual-loop injection-locked opto-electronic (OEO) is proposed and the effect of the fiber loss on the phase noise of OEO is also studied based on this new model.Experiments are conducted to verify the validity,and the results show that the phase noise of os cillation signal does not decrease with the length of fiber if its loss is considered.With the increase of fiber′s length,its loss is growing gradually and reduces the quality factor of the opto-electronic hybrid resonant cavity,and ultimately enhances the phase noise .The results reported in this paper can be applied in engineering application,and provide theory and data support for obtaining the o ptimal length of fiber delay line of low-phase noise OEO.