To explore the relationship between the serum vascular endothelial growth factor (VEGF)level and the severity of obstructive sleep apnea hypopnea syndrome (OSAHS), the concentrations of serum VEGF in 40 OSAHS patients and 9 healthy controls were measured by using ELISA method.Meanwhile the correlation between the concentration of VEGF and parameters of polysomnography (PSG) was examined. Our results showed that the concentrations of VEGF were significantly higher in OSAHS patients with severe hypoxia (536.8±334.7 pg/mL) than in those with mild hypoxia (329.2±174.7 pg/mL) and healthy controls (272. 8±211.0 pg/mL) (P＜0.05 for both). The concentrations of VEGF were also significantly higher in OSAHS patients with hypertension (484.5±261.4 pg/mL) than in those without hypertension (311.0±158.4 pg/mL) and healthy controls (272. 8±211.0 pg/mL) (P＜0.05 for both). There was a positive correlation between the concentration of VEGF and the apnea hypopnea index (AHI) (γ=0.34, P＜0.05). It is concluded that the concentration of the serum VEGF is positively related to the severity of OSAHS. The elevated serum VEGF level may be involved in the pathogenesis of the complications of obstructive sleep apnea hypopnea syndrome.