Spinel Cu_1.5Mn_1.5O₄ thin films were fabricated by one step sol-gel dip-coating method using aqueous solution. The effect of deposition parameters on thickness, surface feature, and optical property of thin films was systematically studied. The results revealed that the increased withdrawal speeds and high concentration of metal ions in precursor were conducive to obtaining thicker films which exhibited excellent solar absorptance. Furthermore, the surface feature derived from the different concentrations of metal ions had a significant effect on optical behavior of the thin film. Consequently, excellent spectral selectivity of the thin film would be achieved by tuning those deposition parameters.