YAG:Ce phosphor was synthesized by a novel simple method, wherein the admixture of three raw materials (Y_2O_3, α-Al_2O_3 and CeO_2) were first acidified by diluted nitric acid to prepare a precursor, followed by a high temperature heating treatment of the obtained pre-cursor under reductive atmosphere. Through XRD measurement and SEM observation, it was found that Y_2O_3, one of the raw material, was firstly dissolved into the diluted nitric acid, and then recrystaUized on the surface of both α-Al_2O_3 and CeO_2 to form a novel nano-flaky hier-archical architectures with the crystalline structure of yttrium nitrate hydroxide hydrates, which makes all the precursor more homogeneous than the admixture of the raw materials from simple mechanical blending method. In the following heating process, the obtained homogene-ous admixtures with hierarchical architectures could easily transform into uniform YAG:Ce phosphor. The resulted YAG:Ce phosphor exhib-ited higher emission intensity than the sample synthesized from mechanical mixing raw materials.