Mn-Zn ferrite was used extensively in a variety of communications. The frequency range is from several hundreds kHz to several MHz. But in the range of -40-80℃ the temperature coefficient of the permeability of the pure Mn-Zn ferrite is rather high which makes the working frequency to drift a little. This causes some trouble in use. In order to improve μ(T) curve, a variety of elements were taken to add to the Mn-Zn ferrite. It has been found out that the μ(T) curve is improved efficiently by adding only a small amount of titanium to the Mn-Zn ferrite. In order to understand the effect of titanium in the material, the neutron diffraction structure analysis of Mn-Zn ferrite containing titanium was carried out. The experimental results show that Ti atom occupies B site, Mn and Zn occupy A site preferentially. In addition the magnetic moment per molcule was also measured. The results are discussed preliminarily.