NOVELTY - Nanocrystal silicon is obtained by plasma-enhanced chemical vapor deposition method. A source gas mixture comprising hydrogen and silane is used. Silane is highly diluted by hydrogen. The flow ratio of hydrogen to silane is 20-120, distance between two parallel electrodes is 0.8-3 cm, high strength plasma excites power density within 160-600 W/cm2, radio frequency, ultra-high frequency, direct current and plasma excitation method are performed, The film deposited soleplate temperature is 150-220 degrees C, and pressure of plasma reactor is controlled within 1-15 mbar.    USE - Manufacture of nanocrystal silicon used for solar energy battery and photovoltaic device.    ADVANTAGE - The nanocrystal silicon is manufactured efficiently.    DETAILED DESCRIPTION - Nanocrystal silicon is obtained by plasma-enhanced chemical vapor deposition method. A source gas mixture comprising hydrogen and silane is used. Silane is highly diluted by hydrogen. The flow ratio of hydrogen to silane is 20-120, the distance between two parallel electrodes is 0.8-3 cm, high strength plasma excites power density within 160-600 W/cm2, radio frequency, ultra-high frequency, direct current and plasma excitation method are performed, The film deposited soleplate temperature is 150-220 degrees C, and pressure of plasma reactor is controlled within 1-15 mbar. An inert gas comprising argon or helium is added into the source gas mixture, where the growing parameter(s) changes following time, comprising periodical change with cycle 3 minutes or less, thereby crystallization degree of nanocrystal silicon is avoided, and crystal silicon volume ratio changes with film plating time. The formed film is in state similar to amorphous silicon. If continuing time of plasma parameter at a point within its change range is more than 10 minutes, then either crystallization degree of nanocrystal silicon is higher, or the material develops into amorphous silicon. At any point in inner portion of growing film, volume ratio of crystal silicon is 45-60%, and average growing rate of film is 10 nm/minute or more. The source gas comprises no impure gas.