There are two limitations present in Archie’s formula. One is the “non-Archie” phenomenon shown in the relationship between porosity and resistivity in tight sandstones, the other is that the effect of fractures on rock conductivity could not quantitatively described by Archie’s formula. The influence of pore size distribution on the relationship between porosity and resistivity of rock is analyzed by using the petrophysical data of tight sandstone core samples from Honghe Oilfield of Ordos Basin, then the hypothesis of “macro-conductive pores” is proposed that the macro-sized pores and micro-sized pores are respectively converted into macro conductive pores according to different proportions. Core electrical experiments data indicate that the macro-conductive porosity and formation factors display a good single linear relationship in double logarithmic coordinates, confirming that the conductivity of macro-conductive pore is approximately the same as the fracture. Therefore, a new calculation method of formation factors is proposed by macro conductive formula, which is not only applicable to tight sandstone formation, but also could quantitatively describe the influence of fracture on rock conductivity. The macro-conductivity formula calculation results are compared with the experimental data of biological limestone samples from T Oilfield of Syria and the previous digital core simulation results, it is found that the formation factors calculated by macro-conductive formula are in good agreement with the values measured by core electrical experimental data and the values simulated by digital core, proving the correct of the macro-conductive formula.