To investigate main influencing factors of repair efficacy for the fatigue crack of FRP-repaired damaged steel members, the finite element method was employed to conduct the parametric analyses of the stress intensity factor(K)for FRP-repaired central-cracked steel plate. The results show that the increase of the FRP cross-sectional stiffness, FRP width and FRP length can decrease the factor K. The values of factor K will not change any more when the FRP length exceeds a certain value. The K can be reduced by decreasing the adhesive thickness and increasing the adhesive shear modulus. The local debond leads to an increase of K value. K values of the single-sided repair are much higher than those of the double-sided repair. Moreover, the increase of the FRP thickness in the single-sided repair cannot effectively reduce K values.