Objective To investigate MVD, TSP-1, TGF-?1 expression in GH-Secreting Pituitary Adenomas by immunohistochemistry, and to correlate data with clinical characteristics.Methods The protein expression of TSP-1, TGF-?1 in 48 surgical specimens (21 invasive cases; 27 non-invasive cases) of pituitary adenomas was measured using immunohistochemical method. The relationship between the expression and clinical properties was examined. MVD was measured by detecting CD34.Results Compared with the noninvasive group, no difference of expression of CD34(t=2.257; P=0.083) was observed. The expression of TSP-1 in invasive group was low. The expression of TGF-?1 was higher in invasive cases than that in noninvasive ones. The expression of TGF-?1 had positive correlations with MVD; but there was no correlation between the expression of CD34 and the invasion of pituitary adenomas. In addition, MVD count was not associated with the expression of TSP-1. Size, sex or rate of recurrence did not influence MVD and TSP-1 expression. Conclusion MVD values do not necessarily represent angiogenesis in pituitary adenomas. TGF-?1 may increase MVD, and TSP-1 does not affect MVD in pituitary adenomas and angiogenesis may be regulated by other pathway.