The effect of reflection on the performance of AM-VSB CATV lightwave systems is analyzed. Usually, there are three kinds of reflection existing in the AM-VSB CATV lightwave systems: multipath interference (MPI), double Rayleigh backscattering (DRB) and external optical feedback. The MPI and external optical feedback can be neglected owing to using the FC/APC connectors and isolated DFB lasers in the system link. It is shown theoretically and experimentally that the DRB is the limitation of the noise induced by reflection.