The purpose of this study is to determine the optimal cutoff price of Hanwoo steers to maximize farmers’ income using real option values. To determine the optimal cutoff price, this study first estimates the carcass weight of Hanwoo steer to reflect the change of weight by time period to the price process. Then, the mean reverting price process, which not only reflects change in weight but also change in grade, is estimated. Finally, this study determines the cutoff price using the universal lattice option pricing model. The results show that the maximum cutoff price of Hanwoosteer is 8,215,284 won at the 4th week of 27 months. Therefore, we can conclude that the optimal selling point of Hanwoo steers is the 4th week of 27 months to maximize income of Hanwoo steers fattening farms.