Objective　To explore the effects of various factors affecting apoptosis of chronic lymphocytic leukemia (CLL) cells mediated by P2Z purinoceptor. Methods　In vitro exposure of CLL cells with P2Z receptors to 1 mmol/L ATP or 0.1 mmol/L benzoylbenzoic ATP (BzATP) for 8 h in the presence of 1.0 mmol/L Mg2+ or other bivalent cations, 150 mmol/L choline in media, 1,2,4 mmol/L EDTA or EGTA, or under different temperature. ATP-induced apoptosis was detected by agarose gel electrophoresis, TdT assay and flow cytometric analysis (FCA). Results　 The results showed that ① Extracellular Mg2+ or Ca2+ stimulated ATP-induced DNA fragmentation in a dose-dependent manner, and the compatible evidence was provided by the inhibition of ATP-induced DNA fragmentation in the presence of EGTA or EDTA; ② ATP-induced DNA fragmentation was completely inhibited by 1.0 mmol/L Zn2+; ③ ATP-induced DNA breaks were not affected by Ba2+, Sr2+, Co2+ when they were substituted for extracellular Mg2+ or Ca2+; ④ Choline, an inhibitor of phospholipase D (PLD) stimulated by ATP through P2Z receptor in human lymphocytes, was also a partial inhibitor of ATP-induced DNA fragmentation, and the results were confirmed by flow cytometric analysis (FCA); ⑤ ATP-induced DNA fragmentation was completely obliterated when the temperature was lower than 10℃. Conclusion　These results suggest that the endonuclease and PLD may be involved in ATP-induced apoptosis in human lymphocytes via P2Z receptor.