Objective To investigate the value of PET-CT in the diagnosis of patient with malignant tumor of the orbit and eyeball.Methods 18 F-FDG PET-CT examination was excuted in 33 patients with orbital or eyeball malignant tumor with the course from 1 month to 5 years.Results All the 33 cases with orbital and eyeball malignant tumor were confirmed by pathologic examination,including lymphoma (16 cases),choroidal melanoma (7 cases),retinoblastoma (4 cases),metastatic tumors to the orbit (6 cases).17 cases showed high FDG uptake at PET-CT in the orbit or the local eye,or in the skin,lymphnode,bone and internal organs,which clearly suggested that the lesions were orbital or eye malignant tumors and metastatic tumors.3 cases need diagnosis with further clinical examinations.13 cases indicated changes due to surgeryand chemotherapy,including 4 cases showed radioactivityconcentrated lesions suggesting residual,recurrent or metastatic malignant lesions.9 cases showed no 18F-FDG uptake,suggesting good therapeutic effect.Conclusion PET-CT fusion imaging combined molecular functional imaging with CT imaging.PET-CT has important value to identify benign and malignant lesions in orbital and ocular tumors,and it also has important clinical value in detecting residual and recurrent lesions and evaluating the therapeutic effect.