Objective:To compare the changes of proliferation and apoptosis of K562 cells after co-culture with human leukemia bone marrow mesenchymal stem cells (LMSC). Methods: The prepared cells were randomly divided into SCG group, SCG+0%FBS group, SCG+0%FBS group and CCG+0%FBS group. Cell counting kit-8 (CCK-8) analytic approach was adopted to detect the optical density (OD) of K562 cells in SCG and CCG groups, and the conditions of K562 cell proliferation under different cultured circumstances were compared. Flow cytometer (FCM) was used to detect the changes of K562 cell cycle after co-culture with LMSC, Annexin V/polyimide (PI) lfuorescence labeling method to detect the changes of K562 cell apoptosis after co-culture with LMSC and serum starvation. Results:After co-culture with LMSC, the proliferation of K562 cells was markedly inhibited, and OD in CCG group was conspicuously lower than that in SCG group. Flow cytometer (FCM) detection on cell cycles demonstrated that after co-culture with LMSC, the proportion of cells in gap phases 0~1 (G0~G1) went up notably, whereas that in phase S went down obviously. Besides, the proportion of cells in phases G2~M was on the rise. K562 cell apoptosis in CCG+0%FBS group was more than in SCG+10%FBS group, and less than in SCG+0%FBS group, indicating LMSC had the function of resisting leukemia cell apoptosis. Conclusion: LMSC exerts the effect of inhibiting the proliferation by blocking K562 cell cycles in phases G0~G1, and inhibiting K562 cell apoptosis induced by serum starvation.