The invention relates to complex phase powder and a preparation method thereof. The preparation method comprises steps as follows: S1, providing ceramic precursor resin and oxide ceramic powder; S2, dissolving the ceramic precursor resin in an organic solvent to obtain a ceramic precursor resin solution, adding the oxide ceramic powder to the ceramic precursor resin solution, and performing stirring at the room temperature to obtain a mixed liquid; S3, grinding the mixed liquid with a grinding process to obtain mixed ceramic slurry, drying the mixed ceramic slurry, and performing powder spraying to obtain the precursor powder; S4, calcining the precursor powder to obtain the complex phase powder. The preparation method adopts a simple process, is low in energy consumption, low in cost andfree from environmental pollution and can be adapted to production and industrial application of large-scale spherical complex phase sub-micron powder. The prepared complex phase powder has good dispersity, uniform particle size, high purity and crystallinity, contains uniform ingredients, has a spherical cladding structure and can achieve the practical purpose.