In this paper, we propose an algorithm to control the forward step cutting of the tool in each tool path for 5-axis surface machining. With present algorithm, the chord error and the change of tool orientation will be controlled in each short forward step linear cutting of the tool path for 5-axis surface machining. First, a suitable tool forward step can be calculated by using iteration method which confirms the chordal height of the tool forward step is less than the preset tolerance of chordal height. Second, in this algorithm, execute a detection of the angle change of the tool orientation between the two successively cutting points. If the detected angle change is larger than the preset value, one or more new cutting points will be interpolated uniformly into this forward step to divide this forward step into several new smaller forward steps for more stable cutting. 5-axis machining is use ball-end mill cutting, if tool orientation normal to part on machining surface, it can cause tool tip mark on machining surface, so we can use tool lead and tilt angle to change tool orientation three direction cosines, can avoid tool orientation singularity problems, this study is use transformation matrix to calculate lead/tilt angle tool position and tool orientation. Finally, we’ll simulation and confirm this method and applicable. In this study, we construct a Matlab program to implement present forward step planning algorithm. An example of a warped ruled surface forward steps computation was performed and simulated in UG CAD/CAM system to demonstrate the validity and practicability of this algorithm. The simulated results show that the chord error and angle change of each forward step are all less than the preset value. In addition, practical machining test was carried out on a CNC 5-axis machining center. The machined surface of the part also has a good agreement with the simulated results in UG system. It reveals that the proposed method is applicable.