The invention provides a process for preparing fresh momordica grosvenori decolored concentrated juice. The process comprises the following steps: saccharifying fresh momordica grosvenori, selecting and washing momordica grosvenori, crushing, performing percolation extraction, performing disc-type centrifugation, performing micro-filtration clarification with a ceramic membrane of 0.45mu m, performing molecular weight ultra-filtration separation, performing decoloring with a polyamide resin, performing decoloring with a decoloring resin, adjusting the pH value with a cationic resin, concentrating with a reverse osmosis membrane, removing residues with a granular activated carbon column, performing micro-filtration clarification with a ceramic membrane of 0.22mu m, performing vacuum concentration so as to obtain an ointment, sterilizing, and performing vacuum packaging, so as to obtain the fresh momordica grosvenori decolored concentrated juice. The flavor and the nutrient components of fresh momordica grosvenori of the fresh momordica grosvenori decolored concentrated juice produced by using the process are maintained, and the juice is nearly colorless and is clear and transparent, is very good in taste, free of after precipitate and high in quality, can be widely applied to food, drinks, medicines and healthcare products, and is simple in production process, advanced in technique, high in automation degree, high in efficiency, low in energy consumption, low in production cost, stable in product quality and high in quality.