Abstract: Complex solutions of Nb⁵⁺,Mg²⁺,Pb²⁺,Co²⁺ and Fe³⁺ were prepared with inorganic Nb₂O₅,Mg(NO₃)₂,Pb(NO₃)₄,Co(NO₃)₂ and Fe₂(NO₃)₃ as raw materials and citric acid and EDTA as complexing agents.The MgNb₂O₆-CoFe₂O₄ precursor was made via a complexing method.Pure MgNb₂O₆-CoFe₂O₄ solid solution was produced through calcining the precursor for 1h at 1000℃.The Pb(Mg_1/3Nb_2/3)O₃-CoFe₂O₄ precursor was prepared via a liquid-packing method,and the Pb(Mg_1/3Nb_2/3)O₃-CoFe₂O₄ precursor separated into ferroelectric phase Pb(Mg_1/3Nb_2/3)O₃ and ferromagnetic phase CoFe₂O₄ when calcined for 1h at 1000℃.The effect of 10% excess PbO addition on the phase transformation from pyrochlore to Pb(Mg_1/3Nb_2/3)O₃ was studied.A pyrochlore-free solid solution of Pb(Mg_1/3Nb_2/3)O₃-CoFe₂O₄ was produced after calcining the precursor for 5h at 700℃.