Aim To investigate the changes of expression of basic fibroblast growth factor (bFGF) and to evaluate the effect of bFGF on angiogenesis in ischemic myocardium after acute myocardial infarction. Methods 30 male infarcted rats were divided into 24h group, 1w group, 2w group, 3w group and 4w group, expression of bFGF protein in ischemic myocardium was detected with immunohistochemical staining. Another 6 infarcted rats were treated with bFGF neutralizing antibody for 2 weeks. Capillary density and arteriolar density were detected in ischemic myocardium. Results Expression of bFGF protein in ischemic myocardium increased at 24 hours after acute myocardial infarction, and peaked at 1～2 weeks after acute myocardial infarction, while gradually decreased at 3 weeks after acute myocardial infarction. The expression of bFGF at 4 weeks after acute myocardial infarction still was above normal level. Capillary density and arteriolar density were significantly augmented at 2 weeks after acute myocardial infarction. Arteriolar density in ischemic myocardium was greatly decreased, but capillary density was in absence of change, after action of bFGF was blocked. Conclusions Expression of bFGF protein in ischemic myocardium after acute myocardial infarction was increased continuously for 1 months or more. bFGF mediates proliferation of arterioles in ischemic myocardium.