The invention relates to a protein-free momordica grosvenori pure-flavor concentrated juice and a production method thereof. The production method comprises the following steps: (1) after washing thefresh momordica grosvenori, squeezing the momordica grosvenori, extracting the pomace with ice water, and merging the juice and an ice water extract; (2) adjusting the pH value to alkaline, adding a protease preparation, performing enzymatic hydrolysis, heating and boiling the material, cooling the material, and performing centrifugation; (3) passing the material through a cation exchange resin column, and collecting an effluent; (4) passing the material through an anion exchange resin column, collecting the effluent, and concentrating the product. The concentrated juice obtained by the methodhas a protein content of less than 0.1%, a mass content of mogroside V as high as 4.53%, and a yield of up to 98%; The obtained concentrated juice is light yellow transparent and thick liquid, the smell is fragrant, the taste is sweet and saturated, no odor is generated, the sugar content is as high as 68 brix, and the sweetness is close to that of sucrose; The production method has the advantages of strong operability, safety, environmental protection and no pollution, and is suitable for industrial production.