Objective To evaluate the feasibility and the factors of prediction error of astigmatism after intraocular lens (IOL) implantation by modified SRK-T, and to study the value of modified SRK-T using for toric intraocular lens power calculation. Methods Retrospective case seriesstudy. This study included 68 patients (106 eyes) underwent phacoemulsification during Oct 2007 to June 2008 in Eye hospital of Wenzhou Medical College. The result of the spherical equivalent calculated by SRK-T and modified SRK-T was compared, and the astigmatism error predicted by modified SRK-T and subjective refraction was compared with vector analysis. Influencing factor of modified SRK-T was analyzed with a multivariate linear regression analysis. Results Spherical equivalent calculated by modified SRK-T and SRK-T was equal. The factors of prediction error in J0 was astigmatism of cornea (KS),J0=-0.108-0.102×KS (P=0.034); and in J45 was axial length (L) and average refraction of cornea (K),J45=1.797-0.019×L-0.031×K (P=0.009). Conclusion Modified SRK-T is a good option for toric intraocular lens power calculation. The influencing factors of prediction include Ks, L and K.