The research analyzed 575 illustrations in children’s picture books published by private sectors (except Hsin-Yi foundation) in Taiwan from 1987 to 2003. The 575 samples were categorized into 11 styles and 28 sub-styles. The results were compared with earlier studies about books published by Hsin-Yi foundation and Taiwan government (Chung-Hua Children’s Books). The results suggest: firstly, there are three developmental periods of the illustrations of picture books published in Taiwan. Secondly, the related meanings of the development are: 1.The range of readers’ age enlarged. The market was expanded to overseas. People of other professions joined children’s book making. The subjects of books changed. All above enriched the spectrum of style. 2.The role and sources of illustrator has been changing; 3.The ways to sell and promote children’s picture books have been changing. 4.The relation among illustration, animation, and cartoon become clear. Thirdly, the conclusions are: 1.The styles reflect polices and ideality of a publisher; 2.The illustrators of different eras formed their styles in different way; 3.There is relation between subjects of books and styles of illustrations; 4.The children’s books become less vocally readable. 5.The relation between styles of children’s picture book and aesthetic education is close; 6.The illustration industry of children’s picture book should be taken seriously.