One dimensional (1D) NaNbO₃ powders have attracted increasing attention for their excellent photo-catalytic and piezoelectric properties, and the stable, moderate and low-energy synthesis of the targets is highly desirable. Herein, a facial solvothermal strategy is adapted to synthesize the one-dimensional (1D) rod-like precursors Na₇(H₃O)Nb₆O₁₉·14H₂O by using isopropanol as the reaction medium. When the precursor is subjected to post-heating treatments, rod-like orthorhombic as well as approximate ellipsoid-like monoclinic NaNbO₃ powders are obtained. Corresponding mechanisms for the stable solvothermal synthesis, morphological evolution and phase transition are further proposed and discussed.