In 1965, Cheng joined the editorial staff of Hau Hsueh Sheng (Good Student) magazine, and started to paint for picture books. After long research, Cheng made progress in his work and gradually built up his confidence.
民國五十四年，鄭明進正式加入兒童插畫的工作行列，他參與「好學生」雜誌的編輯工作，畫了不少封面和插畫，從中逐漸把握繪製插畫的要點。