In this paper, highly ordered nanotube arrays are fabricated via electrochemical anodization of high purity Ti foil in fluorine containing electrolytes. The field emission scanning electron microscopy measurements show that the morphology of nanotube arrays is affected by the two-step anodization process and the polar solvent containing electrolytes. With two-step anodization, the surface morphology of nanotube arrays is orderly and uniform. Moreover, the pore diameter is stupendously homogeneous. The structural parameters of nanotube arrays were improved by the addition of polar solvent, water, to electrolytes. After annealing treatment and Pd nanoparticle doping, the hydrogen sensing characteristics of nanotube arrays were analyzed by measuring its electric resistance response in different concentrations. The results demonstrate that nanotube arrays have high hydrogen sensitivity at room temperature.