NOVELTY - A polycrystalline silicon thin film preparation method involves carrying out radio-frequency magnetron sputtering on a surface of a glass substrate in argon gas atmosphere to form a metal-induced film. The obtained film is exposed to natural oxidation to form a metal oxide thin film buffer layer. A surface of the buffer layer is subjected to sputtering deposition under argon and hydrogen mixed gas atmosphere to form silicon-hydrogen precursor film. The precursor film is subjected to rapid thermal annealing followed by cooling surface of the film.    USE - Method for preparing a polycrystalline silicon thin film that is utilized in a solar battery.    ADVANTAGE - The method enables preparing polycrystalline silicon thin film with high crystallinity, large grain size and quality in a rapid and inexpensive manner. The method enables improving rate of diffusion of silicon atoms toward aluminum atoms, accelerating formation of crystal nuclei, reducing nucleus formation time and promoting crystallization of amorphous silicon thin film.    DETAILED DESCRIPTION - A polycrystalline silicon thin film preparation method involves subjecting glass substrate to ultrasonic cleaning using acetone and deionized water, and drying the substrate. Radio-frequency magnetron sputtering is carried out on a surface of the substrate in argon gas atmosphere at a sputtering rate of 50-250 W to form a metal-induced film, where pressure of argon gas is 0.2-1.5 Pa. The obtained film is exposed to natural oxidation for 12-48 hours to form a metal oxide thin film buffer layer. A surface of the buffer layer is subjected to sputtering deposition under sputtering atmosphere of argon and hydrogen mixed gas, and sputtering power of 250-350 W to form silicon-hydrogen precursor film, where pressure of the mixed gas is 0.2-1.2 Pa. The precursor film is subjected to rapid thermal annealing at 480-550 degrees C for 2-60 minutes, and the surface of the film is cooled to obtain a metal induced polycrystalline silicon thin film.