The Hunter whiteness (HW) is an important quality index of powder in agricultural, food and pigment industries. Relationship between HW of mixed powder and mass percent of each individual powder was investigated. We found a linear relationship expressed by a corresponding equation. According to this equation, the HW of mixed powder was only related to the HW and mass percent of each kind of individual power. Therefore, such equation can simply and rapidly evaluate HW of the mixed powder during the powder matching process. (C) 2008 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights reserved.