NOVELTY - Preparation of high-concentration gradient aluminum-doped zinc oxide monocrystalline conductive thin film involves cleaning monocrystalline silicon, a zinc oxide target and an aluminum target, mounting zinc oxide target on a radio frequency magnetron sputtering device, mounting aluminum target on a direct current magnetron sputtering device and mounting the monocrystalline silicon on magnetron sputtering device, alternately sputtering and depositing aluminum-doped zinc oxide layers and zinc oxide layers and performing coating and annealing diffusion process.    USE - The method is useful for preparation of a high-concentration gradient aluminum-doped zinc oxide monocrystalline conductive thin film, which is useful as passivation layer of thin film solar cell.    ADVANTAGE - The method ensures the preparation of the monocrystalline conductive thin film in a simple and economical manner with large doping concentration gradient variation, uniform gradient, high crystallizing quality, enhanced monocrystalline performance, improved thin film surface and excellent conductive performance.    DETAILED DESCRIPTION - Preparation of a high-concentration gradient aluminum-doped zinc oxide monocrystalline conductive thin film by a diffusion process involves cleaning monocrystalline silicon as a substrate, a zinc oxide target and an aluminum target, mounting zinc oxide target on a radio frequency magnetron sputtering device, mounting the aluminum target on a direct current magnetron sputtering device and mounting the monocrystalline silicon on the magnetron sputtering device, alternately sputtering and depositing aluminum-doped zinc oxide layers and zinc oxide layers on the monocrystalline silicon substrate using zinc oxide target and aluminum target at room temperature by magnetron sputtering process at pressure of 2x 104 pa to 5x 104 Pa for 15-20 seconds, where the sputtering gas is argon gas and oxygen gas at a volume ratio of 1:0-9:1, adjusting the working gas pressure to 0.4-0.7 Pa, performing coating process, where the zinc oxide target sputtering power is 180-200 W and the aluminum target sputtering power is 15-25 W, and maintaining the power of the target materials constant during sputtering and depositing, and performing annealing diffusion process on the monocrystalline silicon substrate in a vacuum furnace at a temperature of 300-500 degrees C for 0.5-2 hours.