With the gradual deepening of shale gas exploration and development and increasing development scale, horizontal well geosteering technologies will be highly required to achieve more accurate geological guidance with the adjustment of drilling trajectory so as to make the horizontal track pass through high-quality reservoir sections. In this regard, a new method for calculating apparent formation dips was proposed, which revolves the strata in a three-dimensional space and takes the highest matching degree of feature points on the logging curves as the principle, and it was applied to the geosteering of horizontal wells. Based on the principle of equal thickness correlation, by this new method the calculation of apparent formation dips is transformed into a global optimization process, and a two-stage method suitable for this new method was also introduced. Compared with those conventional methods, this new method has the following advantages. First, in the case of large-angle torsional orientation and unknown formation dips before the target enters, the apparent formation dips of horizontal sections can be calculated accurately, so can be both stratigraphic tendencies and true dips at the same time. Second, if the vertical thickness of a horizontal well is quite different from that of a selected standard well, and the true thickness of the strata is unknown, the apparent formation dips can be calculated stably and effectively. The tested results from field practices demonstrate that the introduced two-stage method can accurately calculate the comprehensive stratigraphic tendency under the condition of large angle torsion orientation, and the apparent formation dips in the horizontal sections, which is consistent with the actual data. In conclusion, this new method is more suitable especially for the case that the difference of vertical formation thickness is great due to the variation of true formation dips.