本文介绍一种求异面直线距离的有效方法—射影法 ,此法的解题根据是基于下面两个结论 .图 1　结论 1图结论 1　如图 1,若异面直线l1,l2 在平面α内的射影是两条互相平行的直线m1和m2 ,则直线l1,l2 的距离等于直线m1,m2 的距离 .结论 2　如图 2 ,若异面直线l1,l2 在平面α内的射 This article describes an effective way to find the distance from a straight line - projective method. The solution of this method is based on the following two conclusions. Fig. 1 Conclusion 1 Fig. 1 Conclusion If Fig. 1 is different, the straight lines l1, l2 are in the plane α. The inside projection is two lines m1 and m2 that are parallel to each other, and the distances of the lines l1, l2 are equal to the distances of the lines m1, m2. Conclusion 2 As shown in Figure 2, if the lines of the different planes l1, l2 are shot in the plane α