Objective To approach histologically the degree of choroidal invasions of retinoblastoma and their relations with metastasis and prognosis. Methods The pathological sections of 297 enucleated eyeballs with retinoblastom from June 1985 to 1995 were reviewed under light microscope.For the sake of assessing the risk factors of the prognosis of the disease,the graduation of the choroidal invasion was in vestigated in particular,and the follow-up of this genesis were performed as well. Results According to the degree of affection of the intraocular tissues from the tumor cells especially the choroid as the crucial structure,the choroidal invasions were classified into the following 5 categories:0，prereactive phase of retinal pigment epithelium(144/297,48.48%).Ⅰ，reactive phase of retinal pigment epithelium(81/297，27.27%).Ⅱ, early phase of choroidal invasion( 29/297,9.76%).Ⅲ, middle phase of choroidal invasion(17/297,5.72%).Ⅳ， advanced phase of choroidal in vasion(26/297,8.75%).24.24% of cases were found in phases Ⅱ-Ⅳ (so called choroidal invasion).The mortality in patients with phases 0～Ⅲ was found to be 0.4% in the average follow-up period of 51.8 months,and inpatients with phase Ⅳ was found to be 12.0%. Conclusion The retinoblastoma patient with the advanced phase of choroidal invasion (choroida l invasion with great extent) had relative high metastatic rate and poor prognos is. (Chin J Ocul Fundus Dis,1999,15:88-90)