The invention discloses a comprehensive recovery and utilization method for a waste vanadium catalyst. The method comprises the steps that water leaching and reductive acid leaching are sequentially conducted on the waste vanadium catalyst; silicon is separated and recycled by being prepared into sodium silicate through alkaline leaching in a residue leaching mode; single-stage extraction is conducted on leachate through saponification P204, vanadium and potassium are extracted and separated through vanadium extraction technologies of tail liquid concentration and separate re-extraction, potassium is separated by preparing potassium sulphate from raffinate through evaporation and concentration, and vanadium is recycled by preparing vanadium pentoxide from an extraction phase through the processes of back extraction, vanadium precipitation, calcination and the like. Through the extremely high selection characteristic of the saponification P204, not only are the extraction capacity, the utilization rate and the vanadium extraction rate increased, but also influences of iron, phosphorus and arsenic on V2O5 purity are effectively avoided, vanadium precipitation can be directly conducted after back extraction, a high-purity vanadium product is prepared, and the phenomenon that chlorine is released in the oxidization process to pollute the environment is avoided. The method has the advantages that the extraction stages and part of the processes are reduced, the technological process is simplified, the cost is reduced, the economic benefit is increased, and the double effects of making the best use of everything and protecting the environment are achieved.