The automatic nucleic acid extraction instrument is a high-throughput, high-precision nucleic acid extraction equipment, with prepackaged extraction reagents based on superparamagnetic silicon-based magnetic beads, nucleic acid can be extracted and purified from various biological samples such as blood, tissue, cells, body fludis, bacteria and viruses. The instrument realizes the purification and enrichment of nucleic acids through the adsorption, transfer and release of magnetic beads by magnetic rods. The operation is highly automated, fast and simple, and is widely applicable for molecular diagnosis and animal disease detection.