NOVELTY - A pure titanium or titanium alloy as anode and platinum sheet as cathode are electrolyzed in electrolyte, to obtain titanium dioxide nanotube array. The nano-tube array is calcined in presence of oxygen and crystallized. Bismuth sulfide crystal is deposited on titanium dioxide nanotube array using a dimethyl sulfoxide solution comprising bismuth nitrate pentahydrate, sulfur powder and L-cysteine as plating solution. The deposition is carried out in square wave pulse with deposition time of 10-800 seconds, to obtain bismuth sulfide-titanium dioxide nanotube array.    USE - Preparation of bismuth sulfide-titanium dioxide nanotube array (claimed) is used for solar battery, solar-radiation absorber, nanoswitch, thermoelectric photoelectric converter, superconductor and air-sensitive sensor.    ADVANTAGE - The method provides bismuth sulfide-titanium dioxide nanotube array having wide absorption range of titanium oxide in visible light zone and reduced rate of electron hole pair. The nanotube array produces more photon-activated electrons and photon-activated holes under visible light.    DETAILED DESCRIPTION - A pure titanium or titanium alloy as anode and platinum sheet as cathode are electrolyzed in electrolyte under direct voltage of 25-100 V, to obtain titanium dioxide nanotube array. The nano-tube array is calcined in presence of oxygen at 400-500 degrees C and crystallized. Bismuth sulfide (Bi2S3) crystal is deposited on titanium dioxide nanotube array using a dimethyl sulfoxide solution comprising bismuth nitrate pentahydrate (0.05-2 mol/L), sulfur powder (0.1-3 mol/L) and L-cysteine (0.12-3 mol/L) as plating solution in a three-electrode system in which saturated calomel electrode is taken as reference electrode, platinum electrode as pair electrode and titanium sheet of titanium dioxide nanotube array as working electrode. The deposition is carried out in square wave pulse with break ratio of 1:1-1:20, and deposition time of 10-800 seconds, to obtain bismuth sulfide-titanium dioxide nanotube array.