中文摘要：

文章针对图论中寻找最短路径的Dijkstra算法内存占用量大，效率低的缺点，对该算法进行了改进，修改后的算法计算效率是原来的四倍，内存使用量和图中节点数呈线性关系．在此基础上，用新算法求出了激发点和接收点的最短走时路径，并由激发接收点的旅行时结合联合速代法对理论模型和实际场地进行了反演．结果表明：和直射线追踪相比，弯曲射线路径能更好地反演出地质体内部的速度场分布．理论模型和实际探测结果证实改进后的算法是有效的．

英文摘要：

The Dijkstra algorithm which was used in searching the shortest path in graph theory has some defects such as taking much memory, bad efficiency, etc. In this paper, the Dijkstra algorithm was ameliorated. The efficiency of the new algorithm is four times higher than that of the old algorithm, and the relationship between memory used by new method and the number of nodes in graph is linear. Based on this method, the shortest parth of traveling time between the shot and receiver was calculated, and the velocity fields of an academic modal and an actual field were reconstructed by the simultaneous iterative reconstruction technique. The results indicated that the velocity distributing of geology body can be reconstructed better with the bending ray path than with the straight ray path. Theoretical model and the result of practical prospection prove that the new method is effective.