Mass production of low-cost functional nanomaterials is an important issue for the development of nanoscience and nanotechnology. With rich structural, physical and chemical properties, polyoxometalates are important functional materials for both industrial applications and fundamental research. We presented a family of alkali trimolybdate nanowires and nanorods that were synthesized by a one-atmosphere aqueous solution method from a mixture of two solutions, one consisting of (NH4)6Mo7O24 x 4H2O and the other of Li+, Na+, K+ and Rb+ ions, respectively. This family showed clear similarities in their Raman and infrared spectra. By systematic characterizations, we have figured out a universal formula theta(m)(NH4)(2-m)Mo3O10 x nH2O (theta = Li, Na, K, Rb; m = 1,2) for this family of hydrate nanomaterials. Among them, two new phases, namely Li2Mo3O10 x H2O and Rb2Mo3O10 x 3 x 4H2O were recognized. The method was also applied to synthesizing Ag-doped trimolybdate nanowires, and the feasibility for mass production of these nanomaterials with a continuous synthesis experiment was also clear demonstrated. The results of this work offered interesting experimental data for theoretical analysis of the unique growth mechanism.