Ni-Zn ferrite is a kind of important magnetically soft material that has been used widely in medical signal deal and medical apparatus. So, many people are interested in both the prepare process of Zn ferrite (especially the prepare process of nanometer ferrite) and the study of its structure and properties. In this paper the condition in which Ni-Zn ferrite powders was prepared by sol-gel methods was studied. The pH value, calcined temperature, calcined time were investigated. With the designing experiment, the best condition was confirmed. The microstructures and particles size were characterized by means of TEM、IR、XRD and so on.