Usually a certain number of leukocytes can be provided as a reference for diagnosis.By simple scanning blood specimen along a regulated path with the hig h power lens directly,only a few leukocytes can be extracted from lots of captu red ones due to the lower proportion and the uneven distribution of leukocytes in the specimen,which will cause a very low scanning efficiency.A new fast scanning method is proposed,where peripheral bloo d leukocytes in low- magnification microscopic image are located,then the leukocyte detail features i n high-magnification microscopic image are got.The new method improves scanning efficiency and reduces repetition rate based on field border max-min distance cluster means.The experimental results indicate that to scan 1,2leukocytes,the conventional method needs 8－14min,while the new method needs only 1.5－2.0min .The new method reduces the capture times greatly,enhances scanning effic iency and saves computer resources.