Disclosed is a siraitia grosvenorii flavor instant drink comprising a siraitia grosvenorii flavor extract and a siraitia grosvenorii ultrafiltration concentrate, wherein the ratio of sucrose to the sum of glucose + fructose is 2.5-8.0, the total plant protein is 15-35%, the content of mogroside V is no more than 10%. Disclosed is a method for preparing the siraitia grosvenorii flavor instant drink, comprising the steps of: 1) preparation of the siraitia grosvenorii ultrafiltration concentrate: a. water extraction after crushing the fruit of siraitia grosvenorii； b. clarifying； c. ultrafiltration； d. concentration； 2) preparation of the siraitia grosvenorii flavor extract: i. preparing the ultrafiltration extract as described above a-c； ii. adsorption chromatography and collection of the outflow liquid； iii. nanofiltration； iv. concentration； 3) blending the siraitia grosvenorii ultrafiltration concentrate and the siraitia grosvenorii flavor extract at the ratio of 1:1-1:8； 4) sterilizing and drying the blended fluid obtained in the step 3).
