Potassium sodium niobate(KNN) powders were synthesized by a modified sol-gel method,using as starting chemicals potassium carbonate,sodium carbonate,and niobium hydroxide,and,as esterification and chelating agents,respectively,ethylene glycol(EG) and ethylene diamine tetraacetic acid(EDTA)/citrate.The effects of citric acid(CA),EG,and EDTA on the stability of the precursor sol were systemically investigated.The powders and gels were characterized by X-ray diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,and thermogravimetric analysis-differential scanning calorimetry(TGA-DSC).The results indicated that a stable precursor sol was formed when n(CA):n(Mn+)=3:1,n(EDTA):n(NH4OH)=1:3.5,and n(CA):n(EG)=1:2.The xerogel was calcined at 500-950℃ to prepare the KNN powder.Pure KNN perovskite phase with a cube-like structure was synthesized at 850℃ from the precursor sol for a K/Na molar ratio of 1.2.The formation mechanism of the KNN perovskite phase was also discussed. Potassium sodium niobate (KNN) powders were synthesized by a modified sol-gel method, using as starting chemicals potassium carbonate, sodium carbonate, and niobium hydroxide, and as esterification and chelating agents, respectively, ethylene glycol (EG) and ethylene diamine tetraacetic acid (EDTA) / citrate. these effects of citric acid (CA), EG, and EDTA on the stability of the precursor sol were systemically investigated. The powders and gels were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis-differential scanning calorimetry (TGA-DSC). The results indicated that a stable precursor sol was formed when n (CA): n (Mn +) = 3: 1, 1: 3.5, and n (CA): n (EG) = 1: 2. The xerogel was calcined at 500-950 ° C to prepare the KNN powder. Pure KNN perovskite phase with a cube-like structure was synthesized at 850 ° C from the precursor sol for a K / Na molar ratio of 1.2. The formation mechanism of the KNN perovskite phase was also d iscussed