Objective: To observe the effect of roscovitine (ROSC) as some Cyclin-dependent kinases (CDKs), inhibitor onset with the Molt-4 cell lines. Methods: DNA assay of single cells by flow cytometry was used to detect the effect of cell cycle arrest and Annexin-V/FITC assay was used to detect the effect of cell apoptosis when the Molt-4 cell lines cultured with different concentration ROSC in different time points. Results: It showed that ROSC exerted strong inhibitory effect on proliferation and cell cycle progression of Molt-4 cell lines, accumulation of G2/M cells arrested took place after onset with 10 μm and 20 μm ROSC more than 6 h; at the same time, the cell apoptosis of Molt-4 cells would be detected. According with the time and concentration increasing, the cell apoptosis rate would rise. Conclusion: It is concluded that Roscovitine (ROSC)as some Cyclin-dependent kinases (CDKs), inhibitor, has dual effects to Molt-4 cells, not only the effect of cell cycle arrest but also the effect of cell apoptosis.