Abstract: Rotary steering and steering motor are two main steering drilling modes for directional well drilling, and they can meet the steering drilling requirements of most conventional directional wells and horizontal wells. Rotary steering is of high cost and efficiency and steering motor is of low cost and efficiency, so it is often difficult to determine which steering mode to select in the process of program selection and project management. In this paper, the practical experience of Bohai Oilfield was taken as the example. The ratio of average daily footage of steering motor to that of rotary steering in a particular block was taken as the motor efficiency characterization value (E), and then combined with the daily composite drilling cost, the equilibrium point (E₀) of efficiency characterization value at which the cost of rotary steering was equal to that of steering motor was calculated. Afterwards, the steering drilling mode which was economically better was selected by comparingE with E₀, and the quick and convenient application inquiry chart was plotted. Finally, this method was applied to carry out quick economic evaluation on the actual drilling data of over 20 wells in SZ 36-1 Oilfield. It is proved that this method is scientific and practical, and it increases the decision making efficiency of project management and saves the drilling cost. It can be used as the reference for the selection of other speed and efficiency improvement tools and instruments in the field of petroleum engineering.