The invention discloses a method for preparing a cadmium telluride nanowire array. The method is characterized by comprising the following steps of: placing a cadmium telluride target into a radio frequency table (1) in a vacuum chamber (7) of a magnetron sputtering device; placing a quartz substrate on a sample table (2); regulating a distance (d) between the sample table (2) and the radio frequency table (1) to a predetermined distance range; vacuumizing the vacuum chamber (7) to ensure that vacuum degree in the vacuum chamber (7) reaches a predetermined value; heating the quartz substrate to a predetermined temperature range so as to control crystallization conditions of cadmium telluride; filling argon gas into the vacuum chamber (7), and regulating the argon gas pressure intensity toa predetermined range so as to regulate the scattering degree of sputtered cadmium telluride in the process of arriving the quartz substrate, thereby regulating a deposition rate; applying radio-frequency current to control the amount of the sputtered cadmium telluride and regulate the deposition rate; and depositing at a predetermined time.