The invention discloses an electrostatic spinning device for continuously preparing spiral micro-nanofibers and a method of the electrostatic spinning device. The device comprises: a liquid storage cavity, a high-voltage power supply, a motor, a collection electrode, an annular flexible electric brush and a conductive rod; two stainless steel nozzles are inserted into the bottom of the liquid storage cavity; the stainless steel nozzles are communicated with the inner part of the liquid storage cavity; a plurality of air vents are formed in the top of the liquid storage cavity; the conductive rod penetrates through the upper part of the liquid storage cavity; an outer end of the conductive rod is connected with an output shaft of the motor; the annular flexible electric brush slidingly sleeves the conductive rod; the annular flexible electric brush is connected with a positive electrode of the high-voltage power supply; the collection electrode is connected with a negative electrode of the high-voltage power supply. According to the electrostatic spinning device for continuously preparing the spiral micro-nanofibers and the method of the electrostatic spinning device, the spiral micro-nanofibers can be simply, efficiently and continuously prepared, and the mechanical strength and specific surface area of ultrafine electrospun fibers are effectively improved; the device and the method have a wide application prospect in the fields of tissue engineering and textile engineering. Furthermore, the diameter and rotary density of the spiral spun fibers can be matched with different nozzle pore diameters and rotation speeds, and the industrialized advantages of high efficiency and convenience are realized.