Objective To evaluate the effect of propofol on lung cell apoptosis induced by acute pulmonary thromboembolism (APTE) .Methods Forty male SD rats weighing 280-300 g were randomly divided into 5 groups ( n = 8 each) : group Ⅰ sham operation ( group S) ; group ⅡAPTE and 3 propofol groups ( group P1-3). APTE was produced by iv injection of auto-blood clots. Venous blood 0.2 ml was obtained from rat tail vein and placed in a sterile test tube which was kept in water bath at 37 ℃ overnight. The blood clot was cut into thrombi ( diameter 1 mm, length 5 mm) the next day. Fifteen thrombi in 2 ml of normal saline were injected into immediately after iv injection of auto-bloed clots. The animals were killed at the end of 4 h propofol infusion and lung specimens were obtained for determination of lung cell apoptosis rate by flow eytometry and expression of caspase-3, Bax, Bcl-2, Fas, FasL mRNA and protein by RT-PCR and Western blot.The expression of Bcl-2/Bax mRNA and protein was calculated. Results Compared with group S,APTE significantly increased the lung cell apoptosis rate, and expression of caspase-3, Bax, Fas, FasL and decreased the expression of Bcl-2 and Bcl-2/Bax. Propofol infusion significantly attenuated these APTE-induced changes. Conclusion Propofol can inhibit APTE-induced lung cell apoptosis by down-regulating the caspase-3, Fas and FasL expression and regulating the balance between Bcl-2 and Bax expression.