〔Abstract〕 Objective To investigate the role of microfilament sketeton in NCI-H1299 cell apoptosis induced by Newcastle Disease Virus( NDV) and the mechanism related. Methods Morphological observation revealed the changes in cell surface structure and ultrastructure after virus infection; CCK-8 assay was employed to evaluate the inhibitory effect of NDV infection on human NCI-H1299 cancer cells. The apoptosis rate of infected NCI-H1299 cells was detected by flow cytometry; The expression levels of RhoA,ROCK2,F-actin and P-MYPT1 proteins,which were closely related to the microfilament sketeton,were evaluated by western blot analysis after NDV infection for 0,24,36,48 h; Scratch assay and cell migration assay were used to observe the effects of virus infection on migration ability. Results Common inverted phase contrast microscope and scanning electron microscope images showed that the cells changed their normal morphology and structure to fusion and dead shapes after NDV F3 treatment. The microvilli on the cell surface became short,swollen or even shedded. CCK-8 assay results showed that NDV inhibited the proliferation of NCI-H1299 cells in a time-and dose-dependent manner( P<0. 05). Flow cytometry results demonstrated that apoptosis rate increased with NDV F3 infection time within 24 h( P<0. 01).Western blot results showed that the expression levels of RhoA、ROCK2、F-actin and p-MYPT1 proteins have decreased with NDV infection time( P<0. 05). Scratch assay and cell migration assay showed the healing rate of NDV-infected group was slower than that of control group and the infected cell'migration ability was inhibited significantly( P<0. 01). Conclution NDV infection inhibits the proliferation and invasion of NCI-H1299 cells via apoptotic mode. The apoptosis mechanism may be related to RhoA/ROCK pathway which is closely involved in the destruction of microfilament sketeton.