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.