The invention belongs to the field of inorganic non-metal materials and relates to a highfield hydrothermal growth system and a using method thereof. A highfield environment can be obtained simultaneously under high-temperature and high-pressure conditions. The system comprises a direct current adjustable high voltage power supply module, a heating device and a hydrothermal kettle device, whereinthe direct current adjustable high voltage power supply module is introduced to the heating device through a wire connected to the anode and the grounding electrode to be connected to the hydrothermalkettle device in the heating device, so that the circuit communicates. By controlling the temperature and voltage, influence of the highfield condition on growth of a hydrothermal nano or monocrystalnon-polar material is researched so as to obtain shape and performance of a novel nano material. The direct current adjustable high voltage power supply module can provide an adjustable voltage reaching 50 thousand V, the heating device can provide a heat environment and support introduction of the direct current voltage to the heating cavity, and the hydrothermal kettle device can ensure that the material is prepared in a high voltage hydrothermal environment and a highfield environment simultaneously.