Large-aperture potassium dihydrogen phosphate (KDP) crystals are unique candidates for Pockels cells and frequency-doubling devices used in inertial confinement fusion (ICF). However, the low damage threshold of KDP greatly limits the application in all fields. This paper reviews the studies of laser-induced damage mechanisms of KDP in recent years. In addition, our viewpoints about the paths to improve the optical qualities are also discussed. (c) 2005 Elsevier B.V. All rights reserved.