在基于激光同轴送粉的激光制造中，金属粉末流场的分布与特性对制造质量具有重要影响。针对激光同轴送粉金属粉末流速度场提出一种新的分级式搜索算法。通过CCD相机直接记录粒子图像的运动序列，应用新算法编制的粉末流场照片图像处理程序对数字化阵列进行快速分析处理，用分级搜索的方法找到粒子图像上相关度最大的两个小区域，用它们之间的位移除以两次拍照的时间间隔，得到该小区域的速度矢量，就可得到粉末流的速度场。本算法比传统算法减少了运算时间，提高了分析效率。

Manufacturing quality was greatly affected by the distribution and characteristic of metal powder flow in laser manufacture processes based laser beam coaxial powder feeding. Based on the metal power flow field, A new image processing algorithm called different-level searching algorithm was developed .The movement of powder flow was recorded by CCD camera, and the digitized array was rapidly analysed by the new digital image processing technology of powder flow field. This algorithm was used to find the two small regions which are most related, and their displacement was divided by the time duration, then the velocity rector of this region was obtained. Processing the whole picture, the velocity rector field of powder flow was obtained.The new algorithms compared with the old algorithm, can save more computing time and can improve analytical efficiency.