The research is a visual study of humanized devils in illustrations from the 15th century to the present, aiming to improve the accuracy of emotions and information that illustrators convey to audiences with research methods of interview survey, inductive method and morphological charts. One of the important results is the main parameters include characters' interactions, facial expressions, objects, body languages, customs and other elements, and extend to variable parameters for distinguishing humanized devils Then, current and future trends of humanized devils are concerned with characters' interactions, objects, facial expressions and customs. Another important result is the form and the changes of humanized devil. The form of humanized devil in illustrations tends to peace than horror, but the number of demon form and human form is almost equal. This study provides not only a basis for further study in related fields, but also design references for artists, illustrators and designers.