Abstract: The research aims to use the method of probability classification and regression analysis to reveal the relationship between luffa browning degree and its total phenol content, and establish a standard luffa grade based on normal distribution of the browning degree. The browning degree and total phenol were determined among 38 luffa varieties. Furthermore, luffa browning probability was divided into five grades [i.e., extremely low (1), low (2), medium (3), high (4), extremely high (5)] according to four points (i.e., X-1.2818S, X-0.5246S, X+0.5246S and X+1.2818S), and its linear-regression with total phenol was analyzed. The K-S normality testing results showed that the browning degree which ranged from 2.17 to 9.60 conformed to normal distribution, and had an average value of 6.211 and a variable coefficient of 29.77%. There was a significant linear relationship between luffa browning degree and total phenol, and a linear regression equation was established (i.e., y=3.559x- 2.837). The results showed that there was a significantly positive correlation between luffa total phenol and its browning degree.