Ferrography is a commonly used wear monitoring technology.Limited by the depth of field under the high- magnification objective lens,a ferrography image of large wear particles often has only the features of clear local focus.In order to solve the problem of automatic and clear collection and high- magnification image fusion of ferrography large wear particle images under high magnification objective lens,an automatic scanning microscope system was designed and constructed,which can automatically scan and collect the multifocal ferrography images.A multifocal fusion algorithm of ferrography images based on phase consistency was presented to fuse the automatically scanned multifocal images,and clearer wear particle images were obtained.The experimental results show that the automatic scanning microscope system can quickly complete the automatic acquisition process of multifocus ferrography images,and the image fusion algorithm presented has higher image evaluation quality than the traditional wavelet image fusion algorithm,and can obtain clearer image edge information.