Based on the Kosterlitz-Thouless (KT) phase transition model of two-dimensional systems, by introducing the thermal activation energy and the mean height of the pinning landscape into the correlation length, a modified KT transition model has been proposed to study the temperature dependence of the resistivity transition in anisotropic superconductors. This modified KT transition model is consistent with the Coulomb-Gas (CG) scaling law and the Halperin-Nelson relation. And it is applied to study the scaling behavior of the resistivity transition of Tl2Ba2CaCu2Ox (Tl-2212) thin film under various intensities of magnetic field. The calculated mean height of the pinning landscape from the resistivity curve depends on the temperature linearly, which supports the proposed model.