Objective:To investigate magnetic resonance perfusion weighted imaging and its relationship with the grading and the expression of vascular endothelial growth factor (VEGF) and angiogenesis in astrocytomas. Methods: A collection of 34 patients with astrocytomas proved by surgery and pathology were examined by magnetic resonance imaging(MRI), with 26 cases of grade Ⅰ - Ⅱ (low-grade) and 8 cases of grade Ⅲ- Ⅳ (high-grade). MR perfusion images were obtained with spin-echo echo planar imaging (SEEPI) techniques. Expression of VEGF was examined by immunohistochemical method of streptavidin-biotin-peroxidase (SP). The vascular development was measured by micro-vascular density (MVD) which was immunostained with anti-factor Ⅷ-related antigen monoclonal antibody. Results: Both of the expression of VEGF and the angiogenesis in 34 cases of astrocytomas were significantly correlated to the maximum relative cerebral blood volume (Max rCBV) (r= 0. 604, P＜0. 001 ;r= 0. 625, P＜0. 001, respectively). The Max rCBV and the expression of VEGF, MVD in high-grade astrocytomas were significantly higher than that of in low-grade astrocytomas (t= 3.0, P=0.017; t=7.08, P=0.01;t=3.37,P=0. 011, respectively). Conclusion: MR perfusion weighted imaging might be a valuable method in in vivo study of the angiogenesis of astrocytomas and evaluating their malignant degree and prognosis.