The invention discloses an extractive of discoloring, debitterizing corsvenor momordica fruit and a preparation method thereof, the method is as follows: the corsvenor momordica fruit is cleaned, crushed and extracted to juice, the fruit juice is centrifugated, the supernatant fluid enters into the macroporous absorption resin, the resin is washed by water, alkali solvent and water in order, till the effluent liquid is neutral; and then is eluted by 30 percent -65 percent ethanol, the ethanol eluent is collected, ethanol is recovered and dried, and then the extractive is obtained. The technology is simple, the production cost is low, and the production is easy to control; the traditional heating extracting method is replaced by extracting the juice, so the energy consumption is reduced, the color of the obtained extractive is light, the impurity is little, and the product quality is better; the adopted absorption resin achieves better discoloring, debitterizing effects at the same time of enriching the active components completely, the content of momordica glycosides is improved, the pigment and the impurity in the extractive are removed completely through eluting; the obtained product is white powder, the taste is sweet and pure, without traditional bitter taste, wherein, the gypenosides weight content of momordica glycosides can reach over 90 percent, and the V weight content of momordica glycosides can reach over 60 percent.