SMnZn1-xFe2O4 (x=1,0.9,0.8,0.7,0.6,0.5,0.25,0) nanoparticles were prepared by ball-milling hydrothermal and investigated by X-ray diffraction, DTG and TEM, Nanocrystallite grain size was determined by X-ray linewidth to be from 63 (A) to 274 (A). The thermal properties indicate absorbed water still remain at low temperature, crystalline ware will be decomposed from 230 ℃ to 260 ℃, partial Mn2+ will be oxidized near 730 ℃. TEM shows the ferrite particles pocess a spherical morphology and uniform nanosize.