Abstract: SD rats were exposed to subacute dose cooking oil fumes (COF) in order to observe p⁵³ bcl-2, bax protein level of Lung tissues. Rats of test group and negative group inhaled COF(43±4mg/m³×30min/d×20, 40, 60d) and hot air (30min/d×20,40, 80d) respectively,while positive control group was droped B (a) P from trachea(12mg/kg/5d×20,40,60d). An immunohistochemical study was made to investigate the expression level of P⁵³ gene. In the study,the level P⁵³ of COF and B(a)P group are higher than control group. A close timeeffect relationship was existed in COF group bcl-2 protein level was as like as p⁵³ protein. The level of p⁵³、bcl-2 protein of adenic metaphasin arcad precancerous lesion tissues were higher than other lung tissues,wheras the level of bax protein was lower than control group. This suggested, the expression of apoptosis related to genes may play role in the pathological changes exposed to COF.