As a firm and loyal follower of Chu Tsu School，Korean Confucian I Hwang（Toegye） tried his best to interpret and defend Chu Tsus theories through his whole life，the doctrine of righteousness and utility is just one case.It is a pity that the researchers have not found until today that the text which Toegye used to defend Chu Tsu is actually not written by Chu Tsu himself but his second generation disciple Ye Cai.This essay reveals in details the truth and points out that Neo-Confucianism of Chu Tsu school from China to Korea is of one kind of universal value in pre-modern East Asia.