Abstract: Objective Study on direct killing effect of NDV on human tumour cells. Methods NDV was added into the culture dishes of human cell lines of hepatic carcinoma,gastric carcinoma,pancreatic carcinoma,cervical carcinoma and normal fibroblast,repectively,and control groups were set as well . The status of growth and replication of virus was measured and observed at 8,16,24,36 and 48 hr. Results Fibroblast cells and control group cells grew well,whereas the growth of tumour cells in experimental groups reduced gradually,and cells fusion and lysis appeared.At 48 hr,virus titer in tumour cell supernatant was comparatively high while it was zero in fibroblast supernatant. Conclusion NDV has comparatively strong affinity with tumour cells,andit can replicate in tumour cells,and can kill tumour cells directly.It is innocuous to normal cells.