The invention discloses a carbon-coated metal ion-doped sodium vanadium phosphate composite cathode material prepared by a freeze drying method, as well as a preparation method and application thereof. A preparation process comprises the following steps: (1) completely dissolving a vanadium source, a sodium source, phosphate, a citric acid and a metal ion source in de-ionized water, and freezing a mixed solution into ice after uniform stirring; (2) performing freeze drying on a frozen ice block in a freeze dryer to obtain a drying product; (3) performing heat treatment on the drying product in the air to obtain sodium vanadium phosphate precursor powder; (4) uniformly grinding the powder, and performing heat treatment cooling in a protective gas atmosphere to obtain the material. The material is applied to a sodium ion battery cathode material, the electrochemical performance of the material is improved by the porous structure of the material, and the electrical conductivity and the structural stability of the sodium vanadium phosphate material can be effectively improved by ion doping. Compared with undoped sodium vanadium phosphate and a material for which the freeze drying method is not adopted, the prepared material has higher charge and discharge specific capacity and higher cycling stability.