Abstract: Objective To study the effect of proliferation and radiation sensitivity of cardiac muscle cell lysate on human nasopharyngeal carcinoma CNE2 cells. Methods Lysates of rat cardiac muscle tissue of＞10kD，＜5kD and 510kD were obtained by ultrafiltration centrifugation method， including CMCLnr from neonatal Wistar rat and CMCLar from adult Wistar rat； culture solutions of rat cardiac muscle tissue of＞10kD，＜5kD and 5-10kD were obtained too， CMCMnr from neonatal Wistar rat and CMCM20dr from 20day old neonatal Wistar rat. Survival rate of CNE2 cells was detected when it was treated with 0.3mg／ml different molecular weights of CMCLnr， CMCLar， CMCMnr， CMCM20dr and 1.26μg／ml DDP for 48h. The radiosensibility of CMCLnr（5-10kD） and topotecan（TPT） was detected and singlehit multitarget model was used to plot survival curve.CNE-2 cell cycle and apoptosis were measured by flow cytometer. Results Compared with control group， 5-10kD CMCLnr， CMCLar， CMCMnr， CMCM20dr could significantly inhibit the survival rate of CNE-2 cells（P＜0.05）. They had the same anticancer activity as platinum （P＞0.05）. The values of D0， Dq， N and SF2 of CNE-2 cells received radiation treatment alone were 1.185Gy， 0.676Gy， 3.729 and 69％.Those of CNE-2 cells received radiation plus CMCLnr （5-10kD） were 0.762Gy， 0.600Gy， 6.147 and 25％. SERD0， SERDqand SERSF2were 1.555， 1.127 and 2.760. The apoptotic rate of CMCLnr+radiation group was （19.34±0.23）％，which was higher than that in topotecan+radiation group and single radiation group（P＜0.05）. Conclusion The cardiac muscle cell lysate can inhibit the proliferation of CNE-2 cells and has shown radiosensitizing effect in vitro on CNE-2 cells. The radiosensitizing mechanism may be related to the induction of S phase arrest and apoptosispromoting effects.