OBJECTIVE To evaluate the value of color Doppler ultrasonography (CDU) in the diagnosis of intraocular lesions. METHODS 82 cases of intraocular diseases were examined by high-resolution CDU (7.5 mHz), and the blood flow pattern was evaluated at the base of two-dimensional image. RESULTS CDU might show the blood flow of retinal vessels in all 21 cases of retinal detachment, no blood flow could be detected in 21 of 22 vitreous hemorrhages and/or membranes, and only in one case with diabetic proliferative retinopathy did fine blood flow be seen. Intratumor blood flow with branchy pattern could be detected in 17 of 18 cases with choroidal melanomas and 3 of 4 cases with choroidal metastatic carcinoma, and spectral analysis revealed high-resistance, simulating arterial blood flow waves. In 5 cases with choroidal hemangioma, intratumor blood flow with filled or sparkled pattern was detected, and the spectral analysis revealed both arterial and venous blood flow waves. No blood flow in the lesion was detected in simulating benign lesions i.e. 5 choroidal hemorrhages and 2 subretinal hemorrhages. In 3 cases (4 eyes) with persistent hyperplastic primary vitreous (PHPV), CDU showed band-shaped arterial blood flow coursing from optic nerve disc to the posterior surface of the lens in the vitreous cavity. CONCLUSIONS CDU is helpful in the differential diagnosis among retinal detachment, vitreous hemorrhage, vitreous membrane, malignant choroidal melanoma, choroidal metastatic tumor, choroidal benign lesion or hemangioma, PHPV and lesions with white pupil.