Insect cell lines(Sf)isolated from female fall armyworm,Spodoptera frugiperda(Sf),are widely used as hosts for recombinant protein production in baculovirus insect cell system(BICS). However,in 2014,Ma H found that these cell lines were contaminated by a virus now known as Sf-rhabdovirus(Sf-RV). This raises a potential security issue that may adversely affect BICS as a com. platform for recombinant protein production Therefore,we screened a Sf-RV-neg. Sf9 cell line named Sf9-ZY. Nested RT-PCR detection results showed that Sf-RV was not detected in Sf9-ZY cells during 25 generations of continuous culture. The general characteristics of Sf9-ZY cells,including average growth rate and diameter,are basically the same as Sf9 cells;the level of infectious baculovirus production in Sf9-ZY cells and Sf9 cells is the same level;the level of recombinant baculovirus expression in Sf9-ZY cells and Sf9 cells is the same level. These results suggest that Sf9-ZY cells can be used as an improved alternative host to avoid potential safety risks associated with the production of recombinant proteins by Sf9 cells contaminated with Sf-RV.