Objective To observe the vascular endthelial cellular apoptosis induced by transpupillary thermotherapy (TTT). Methods Vascular endothelial cells (VEC) cultured in vitro were treated with TTT, hyperthermia and TTT combined with indocyanine green (ICG) pretreatment. The cellular apoptosis was detected by doublelabelled flow cytometer (annexin Vfluroescein isothiocyanate and propidium iodide) analysis, fluorescent microscopy, nucleolus stainned with DNA dye hoechst 33258, DNA ladder detection and electron microscopy. Results Without significant rising of the temperature, TTT couldnprime;t increase the apoptosis of VEC. Pure hyperthermia and TTT combined with ICG pretreatment could increase apoptosis of VEC significantly, and the effect of the latter method was more obvious. The higher power of TTT was used and the longer duration the cells were cultured, the higher apoptosis rate of VEC was. Conclusion The induction of apoptosis of VEC might play an important role in the mechanism of the occlusion of CNV by TTT, and combining with ICG may obviously enhance the apoptosis rate at the same temperature, which may supply a theoretical basis for promoting the clinical effect of TTT.