To develop a good host material for red phosphors as well as a model for clarifying the underlying correlation between structure and properties, tetragonal phased LaVO4:Eu was synthesized via an ethylenediamine tetra-acetic acid (EDTA) assisted hydrothermal method. The challenging transformation from monazite to the metastable zircon structure for LaVO4:Eu resulted in a remarkable improvement of the luminescent properties. This improvement was rationally analyzed and the impact of structure on luminescent properties was explored. Based on these results, structural transformation-induced luminescent properties improvement was proposed as an efficient means to improve the performance of doped-insulators.