The invention discloses a method of refining medicinal xanthan gum, which comprises the steps of S1, crosslinking calcium alginate and zeolite microspheres in industrial xanthan gum solution to form gel precipitate, and filtering to obtain precipitate A; S2, dissolving the precipitate A in an alcohol-bearing solution, and filtering to obtain filtrate; S3, allowing the filtrate to form precipitateB in an alcohol solvent, wherein the alcohol solvent is an alcohol in the alcohol-bearing solution of the step S2; S4, washing the precipitate B of the step S3, and drying to obtain the medicinal xanthan gum. The method herein has the advantages that calcium alginate and zeolite microspheres are crosslinked to separate xanthan gum by precipitating the industrial xanthan gum, and the finished xanthan gum can meet the medicinal standards and meets the quality standard for medicinal xanthan gum in 2015 version volume IV.