The monascus sp. was selected as the starting strain by the mutagenic treatment of ultrasonic wave. A high yield mutant producing Monascus pigment and Monacolin K was obtained by the method. During the fermentation, the broth was subject to intermitted ultrasonic wave treatment. The results indicated that content of the Monascus pigment and Monacolin K produced by the mutant increased 29.74% and 39.96%, respectively, compared with those from the starting strain. (c) 2005 Elsevier Inc. All rights reserved.