The invention discloses a preparation method of a superfine cadmium sulfide particles-sensitized titanium dioxide nanotube array, comprising the following steps of: 1) pretreating the surface of a substrate material, carrying put anodic oxidation to obtain pure TiO2-NTs by taking mixed solution of NH4F and H3PO4 as electrolyte, taking a Ti slice as a working electrode Pt slice and a counter electrode,, and roasting an obtained sample, to obtain an anatase type TiO2-NTs thin film; and 2) ultrasonically treating the sample obtained in the step 1), carrying out electro-deposition by taking CdCl2 as electrolyte to obtain Cd/TiO2-NTs, carrying out roasting and thermal oxidation to obtain CdO, carrying out ion exchange in Na2S solution, and withdrawing to obtain CdS/TiO2-NTs. In combination with the electro-deposition and the ion exchange, the superfine CdS particles are evenly dispersed at the tube opening of the TiO2 nanotube array and in the tube, so that the effective contact area between the CdS particles and the TiO2 nanotube array can be increased, therefore, the charge transfer among interfaces can be increased, the photoelectric conversion efficiency is higher, and the activity of the photo-electrically and catalytically degraded organic pollutants can be improved.