Objective To evaluate the influence of histopathological invasion on the survival prognosis of patients with unilateral retinoblastoma. Methods Seventyseven patients with unilateral retinoblastoma who were treated by primary enucleation were followed up after treatment. The patients were followed up for a median period of 49 months (range from 1 week to 89 months). The survival data were collected by follow-up appointment, telephone or letter. The Kaplan-Meier method was used to calculate the cumulative survival rate and curve comparison was done with the log-rank test including the degree of the optic nerve invasion, choroidal invasion, choroidal invasion with or without optic nerve invasion, as well as the anterior segment involvement or not. Results The two years survival rate was 88.31%. The survival rate of the group with tumor involvement in the cut end of optic nerve was 16.67%, and significantly lower than other groups with optic nerve involvement (chi;2=19.51, 18.42, 18.42, 14.39; P=0.000 0).The survival rate of the group with massive choroidal invasion and scleral involvement was 60.00% and significantly lower than the group without choroidal involvement (chi;2=7.69，P=0.005 5). The survival rate of the group with optic nerve involvement and massive choroidal invasion was 75.00%, and the survival rate of the group with optic nerve involvement and scleral or orbital invasion was 60.00%. The survival rate of those two groups were significantly lower respectively than the group only with optic nerve invasion（chi;2=4.25, P=0.039 3;chi;2=7.59, P=0.005 9）.There was no significant difference of survival rate between groups with or without anterior segments involvement (chi;2=0.05，P=0.823 5).Conclusions The risk factors for RB death include the surgical marginal involvement of optic nerve, massive choroidal invasion combined with optic nerve and scleral involvement. The anterior segment involvement has no effect on prognosis of patients with unilateral retinoblastoma.