Polycrystalline silicon production is a typical high energy-consuming industry, in which a stable hydrogen supply is required, and the annual electricity consumption of the hydrogen production process is considerable. Hydrogen production equipment has a wide range of adjustable characteristics; meanwhile, hydrogen storage does not have dynamic depletion issues and it has good energy storage characteristics. Therefore, equipment capacity planning and operation optimization of the hydrogen production & storage system in polycrystalline silicon production lines have certain value in increasing the proportion of new energy consumption in the energy supply system of polycrystalline silicon production lines, and reducing hydrogen production costs. This paper utilizes low-cost photovoltaic power generation in the northwest region of China to supply the hydrogen production system. A comprehensive scheme of photovoltaic power supply, hydrogen production & storage, and optimized operation is adopted to optimize the photovoltaic power generation capacity, hydrogen production equipment capacity, and hydrogen storage equipment capacity, and to perform the operation optimization, which can effectively reduce the hydrogen production cost of polycrystalline silicon production lines, and increase the proportion of green electricity usage in polycrystalline silicon production lines.