Abstract: Nearest neighbor query of spatial database has received more and more attention in recent years. According to the abstract degree, nearest neighbor query has three main categories: nearest neighbor query between point and point, nearest neighbor query between point and line segment, and nearest neighbor query between line segment and line segment. At present, the former two nearest neighbor queries. have received more research more than the last one that lacks relative literature. In this paper, the question of nearest neighbor query between line segments and line segment is put forward. It aims at solving some instance which spatial object can not be abstracted as a point. Nearest neighbor query between line segment and line segment has wide area of application in realism. According to whether two line segments are intersected, it has two categories: intersected line segment and no intersected line segment. And the position between no intersected line segments has nine categories. Every one has been studied and implemented nearest neighbor query between line segment and line segment. The filter rule, theorems and the query algorithms of the nearest neighbor query between line segment and line segment are proposed. Furthermore, the experiment analysis is also given. The method of this paper can implement the nearest neighbor query between line segment and line segment better and has high query efficiency.