The invention discloses a galium arsenide polycrystal magnetic field growing furnace and a growing method, and relates to galium arsenide polycrystal, in particular to a galium arsenide polycrystal magnetic field growing furnace capable of controlling galium arsenide polycrystal synthesis through magnetic field induced vortex as well as a growing method. The galium arsenide polycrystal magnetic field growing furnace and the growing method are characterized in that the growing method utilizes the galium arsenide polycrystal magnetic field growing furnace for synthesis, wherein the galium arsenide polycrystal magnetic field growing furnace comprises a furnace chamber and a magnetic field device; the furnace chamber is cylindrical, and is embedded into the magnetic field device; the induced vortex is generated through the magnetic field device in the galium arsenide polycrystal growing process, and polycrystal growth is controlled by the induced vortex. According to the galium arsenide polycrystal magnetic field growing furnace and the growing method, the solid liquid interface control difficulty is reduced, probability of arsenic leakage phenomenon is avoided, and the utilization ratio of the high-purity arsenic and high-purity gallium raw materials is improved.