The apparent resistivity curves of conventional dual laterolog often present polarization angle at the stratigraphic interface，resulting in distortion of the curve form and occurrence of“pseudo thin layer”phenomenon，which seriously affects the accurate division of the stratigraphic interface and the accurate calculation of the true resistivity of the strata.Based on the finite element numerical simulation technique，the mathematical model of dual laterolog was established. The effects of surrounding rock resistivity，layer thickness，reservoir anisotropy，well diameter and well inclination on polarization angle and amplitude of dual laterolog apparent resistivity were studied. The results show that the difference between the resistivity of the target layer and the resistivity of the surrounding rock is larger，and the polarization angle of the dual laterolog is more obvious. The effect of layer thickness on the polarization angle is complicated. When the thickness of the strata is thinner than the thickness resolved by instrument measurement，the polarization angle disappears. The anisotropy of the reservoir will cause the amplitude of the polarization angle to change，but the influence on geometry of the polarization angle is small. As the well diameter becomes larger，the polarization angle tends to disappear. The larger the well inclination is，the gentler the polarization angle is. The polarization angle of dual laterolog apparent resistivity curve is the result influenced by many factors. In the work of polarization angle correction，all factors should be considered comprehensively.