Abstract: Objective To investigate the effect of nuclear factor 90 （NF90） knockdown on proliferation of hepatocellular carcinoma （HCC） cell and explore its mechanism. Methods The oligonucleotides targeting NF90 were cloned into the PLKO plasmid and packaged with lentiviral shRNA to knockdown NF90 （with green fluorescent labels and G418 resistance）. The hepatocellular carcinoma cells QGY-7703 and SMMC-7721 were divided into control group and intervention group. The virus containing random sequence shRNA and targeting NF90 shRNA were infected， respectively. After 48 h， positive cells were stained with green fluorescence， and the positive monoclonal cell lines were screened by G418. The expression level of NF90 protein was identified by Western blotting. Finally， a cell line named shRNA-ns was selected in the control group. Two cell lines of NF90 knockdown named shRNA-1 and shRNA-2. Cell growth activity was detected by CCK-8 and clone formation analysis. The relationship between NF90 and PARP1 was detected by fluorescence localization assay. Results The expression of NF90 in shRNA-1 and shRNA-2 cells was significantly lower than that in shRNA-ns cells， indicating that the knockdown of NF90 by lentivirus was effective. Compared with shRNA-ns cells， shRNA-1 and shRNA-2 cells were slow to grow and the number of clones was decreased with statistically significant difference （P＜0.01）. NF90 and PARP1 bind to each other in the cell and co-localize in the nucleus. Conclusion NF90 knockdown inhibits HCC cell proliferation， and NF90 may affect HCC cell proliferation by interacting with PARP1.