An automated production line for preparing cannabidiol (CBD) extracts is disclosed. The production line comprises sequentially a solvent dispensing tank, an extraction tank, a first concentration tank, a dilution tank, a filter, a second concentration tank, a chromatography column and a crystallization device. Each of these elements is connected to and controlled by a central controller. The controller can control the operation of these elements such that one element may operate independently of the other. Hence, each of these elements may operate for a sufficient period of time to allow the completion of the particular CBD production step carried out by that particular element. The amount of operations by humans may be reduced, thereby increasing the production efficiency.