Abstract: Space configuration of well trajectory is one of the major accounts that determines the lateral force, and especially, the orientation force on bit. T he curvature direction of well path is used to describe hole orientation in this paper, and its influence on bit lateral force, the influencing tendency is also investigated. The results show that the the curvature direction of well path could be used effectively to illustrate how the space configuration of well trajectory affect bit lateral force, combining the use of hole curvature. Specifically, the orientation force on bit is approximately zero when the the curvature direction of well path is 0°, and the maximum value appears when the the curvature direction of well path is 90° or 270°. It shows that the curvature direction of well path and hole curvature are the two major causes that produce orientation force on bit, when formation condition is not taken into consideration. This study is helpful for well trajectory control in field drilling.