In this paper, a novel reflector design with serrated resistance films (R-films) frame for compact antenna test range (CATR) is proposed. The CATR is an essential system for antenna testing at 5G millimeter-wave frequencies, which can convert spherical incident waves into quasi plane waves by parabolic reflectors in relatively short distance, thus forming a quiet zone (QZ) where large devices under test (DUT) can be tested. Conventional reflectors with metal edges can lead to serious edge diffraction and usually increase noise level inside QZ. In order to mitigate strong edge diffraction at low-frequency, this paper proposes a reflector with resistive films (R-films) frame, which mainly mitigates edge diffraction at the low-frequency bands and achieves better QZ performance without increasing metal area. The novel serrated R-films frame have low edge diffraction and is supported by a substrate to achieve better stability and connectivity. The proposed reflector/with R-films frame can be considered as a competitive alternative to the traditional reflector.