Objective To investigate the changes of hypoxia-inducible factor (HIF-1α, HIF-2α) expression level in lung cancer A-549 cells under normoxic conditions, different hypoxia durations, and different oxygen concentrations. Methods A549 cells were divided into normoxic group, time control group, and oxygen concentration control group. Western blot was used to detect the expression of HIF-1α and HIF-2α in A-549 cells.Results The expression of HIF-1α and HIF-2α protein were lower under normoxia and significantly increased under hypoxic conditions. The difference was statistically significant. The lower the oxygen concentration, the more HIF-1α and HIF-2α protein expression levels were. The differences between high and high were statistically significant. The expression of HIF-1α protein increased at 2 h after hypoxia, peaked at 8 h, appeared plateau at 8 to 16 h, and decreased at 32 h, with a statistically significant difference. HIF-2α proteins gradually increased with prolonged hypoxia. Conclusions Under hypoxic conditions, the expression of HIF-1α and HIF-2α are increased, and the expression of HIF-2α has a time-dependent pattern, which may have more important biological significance.