Directional drilling is playing a great role in mineral exploration and exploitation. Accurate prediction of the well inclination and azimuth at the well bottom can reduce drilling cost. In this paper, a model for prediction of increment in well inclination and azimuth is established by using of data processing for well inclination, azimuth, and toll face as well as interval and rate of well inclination build-up. Compared with the general formula of directional wells, it has a high precision and is capable of predicting trace parameters of the directional well bottom rapidly at site.