The invention discloses a method for preparing high purity rhodium trichloride by removing impurities from a liquid phase digestion solution of a waste rhodium catalyst. The method is characterized by comprising the following steps: step one, taking liquid phase digestion solution obtained by digesting waste rhodium catalyst for carbonyl synthesis with concentrated sulfuric acid and nitrate, adjusting to pH value to 1-5 by using sodium hydroxide, dropwise adding a sodium oxalate solution with stirring so that the solution becomes turbid, continuing adding the sodium oxalate solution until complete precipitation, stirring for 20-40 min and filtering to obtain the filtrate, wherein the concentration of sodium oxalate solution is 1-10 wt%; and two, directly heating the filtrate obtained in the step one or diluting the filtrate with deionized water by 10 times and heating to a boiling state, adjusting the pH value to 8 with 1%-15% sodium hydroxide solution, stirring and filtering to obtain a rhodium gel; and dissolving the rhodium gel in 6 mol /L hydrochloric acid, and evaporating, concentrating and drying the solution to obtain high-purity three rhodium trichloride. The method of the invention is applicable to recovery of noble metal rhodium from the waste rhodium catalyst from carbonyl synthesis, and is economical and environment-friendly; and the method has the advantages of mild reaction conditions, simple operation and easiness for industrialization.