NOVELTY - A semiconductor nanocrystal-crystalline silicon heterojunction composite preparing method involves selecting wide gap semiconductor nanocrystal-crystalline silicon heterojunction material. The crystalline silicon chip is preprocessed with cleaning liquid. The silicon chip is cleaned with distilled water and dried. The semiconductor nanocrystals are deposited by immersing preprocessed silicon chip in precursor solution, and drying the silicon chip. The nanocrystal deposited-crystalline silicon chip is annealed and etched to obtain the finished product.    USE - Method for preparing semiconductor nanocrystal-crystalline silicon heterojunction composite that is utilized in solar photovoltaic cell.    ADVANTAGE - The method enables preparing semiconductor nanocrystal-crystalline silicon heterojunction composite with direct-wide bandgap and unique features, improving minority carrier lifetime and quantum efficiency of crystalline silicon cells, and improving photoelectric conversion efficiency of solar photovoltaic cells.    DETAILED DESCRIPTION - A semiconductor nanocrystal-crystalline silicon heterojunction composite preparing method involves selecting wide gap semiconductor nanocrystal-crystalline silicon heterojunction material, and preparing 0.05-15 mol/l cleaning solution and semiconductor precursor solution containing 1-50 mg/ml metal ions and 0.01-30 mg/ml dispersing agent. The crystalline silicon chip is preprocessed with cleaning liquid for 1-200 seconds and dead layer on surface of the silicon chip is removed. The silicon chip is cleaned with distilled water for 1-10 minutes and the cleaning liquid is removed. The silicon chip is dried. The semiconductor nanocrystals are deposited by immersing preprocessed silicon chip in the precursor solution at 4 cm/minute for 1-200 seconds, and drying the silicon chip. The nanocrystal deposited-crystalline silicon chip is annealed at 100-1000 degrees C for 1-60 minutes to obtain nanocrystal-silicon heterojunction composite. The obtained composite is etched to obtain the finished product.