This present invention discloses a method for preparing a lipolysis-stimulating soy protein hydrolysate, proceeding a hydrolysis reaction, which is a predetermined concentration of soy protein mediated by Flavourzyme in a predetermined hydrolysis conditions, wherein Flavourzyme versus the soy protein is 1:100, and the optimal hydrolysis conditions including reaction pH value 7&tilde7.5, reaction temperature 40&tilde50° C. and hydrolysis time 100&tilde150 minutes. This invention further discloses nine recombinations of isolated peptide sequences from the soy protein hydrolysate including Val-His-Val-Val, Leu-Leu-Leu, Leu-Leu-Ile, Leu-Ile-Leu, Leu-Ile-Ile, Ile-Leu-Leu, Ile-Leu-Ile, Ile-Ile-Leu and Ile-Ile-Ile.本發明所揭一種製備促脂解大豆蛋白水解物之方法,首先係先將一配置好預定濃度之分離大豆蛋白,再加入一風味蛋白酶(Flavourzyme)於一最適水解條件下,進行水解反應,其中,該分離大豆蛋白與風味蛋白酶之比例為100:1,而該最適水解條件係如下:反應酸鹼值介於7~7.5間、反應溫度為40~50℃、水解時間為100~150分鐘,得到一具有極佳之促脂解活性之大豆蛋白水解物。本發明係更進一步分離鑑定出該大豆蛋白水解物中之活性胜肽序列具有九種組合,分別為Val-His-Val-Val、Leu-Leu-Leu、Leu-Leu-Ile、Leu-Ile-Leu、Leu-Ile-Ile、Ile-Leu-Leu、Ile-Leu-Ile、Ile-Ile-Leu及Ile-Ile-Ile。