AIM:To compare the hemodynamic changes before and after trabeculectomy in glaucoma ( 32 eyes).METHODS: Color Doppler ultrasonograph was used to measure retrobulbar blood flow of normal controls and 32 patients before surgery and at 2 and 12 weeks after trabeculectomy, respectively. The measurements included peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistent index (RI) in central retinal artery(CRA) short posterior ciliary artery(SPCA) and ophthalmic artery(OA).RESULTS: Compared with normal control group, PSV and EDV were decreased while RI was elevated in CRA, SPCA and OA of glaucoma group (P<0.01). The hemodynamic of glaucoma group had significant improvement after trabeculectomy, PSV and EDV were elevated while RI was decreased. Intraocular pressure of glaucoma patients after trabeculectomy restored to the normality, PSV,EDV and RI of CRA, SPCA and OA in glaucoma group were still inferior to normal control group (P<0.05).CONCLUSION: Glaucoma patients have more insufficiency of blood flow than normal person. Trabeculectomy can effectively improve ophthalmic blood flow. Color Doppler imaging is a potential approach to evaluate and monitor glaucoma.