The invention relates to a method and a device for compositely preparing ultrafine powder by adopting jet current electrostatic recombination. The method is characterized by comprising the following: step 1, placing powder material inside a vacuum drying box for drying; and step 2, carrying out jet current crushing of the dried powder material in high-speed air current and electrostatic dispersion inside a high-voltage electric field charged area to obtain ultrafine powder. The device is characterized in that an air passage of an air compressor is connected with a jet current electrostatic disperser and a collector in turn; and the front end of the jet current electrostatic disperser is provided with a voltage regulator and a feeding bin. The method and the device have the advantages thatthe method has simple operation, low cost, high efficiency and even distribution of prepared powder granularity; and no chemical modifying agent, such as coupling agent and surfactant, is adopted during powder preparation, thereby preventing impurity pollution. The method and the device can be widely used in precision ceramics, magnetic material and rare earth material, and the like which has higher requirements on powder purity as well as in industries not suitable to adopt a wet method to prepare powder.