Augmentative and Alternative Communication (AAC) system could offer the service of symbol, aid, technology and strategy for people with temporary or permanent communication disabilities. In the AAC system, symbol has been regarded as the fundamental element. However, most related studies have focused on the comparisons of AAC symbols within systems and few have converted forward insights to common visual design principles for future core vocabulary symbol display. Meanwhile, limited literatures have recruited aphasia adult participants who are accounted for the largest proportion of communication disorder population. Therefore, the study was concentrated on the discussion of symbol transparency (the iconicity perspective of usability) with aphasia adults. At phase I, AAC symbols were classified as personal related noun, object noun, verb and adjective with opinions from researchers. Afterwards, HCI professionals with at least five years experiences, took heuristics evaluation and designed the symbols for each word-class with static photograph and illustrated based on current AAC symbol styles. The analysis showed that the noun symbols with photograph resulted in high transparency and preference while verb and adjective symbols resulted in low transparency. Based on the improving of the verb and adjective symbol transparency and preference, without static status, the two dynamic forms of static with supplement lines and animation were also studied (three levels in total) at phase II to investigation whether the dynamic characteristics could advance the symbol transparency and preference of verb and adjective. The findings demonstrated that dynamic forms could enhance most of the verb and adjective transparency and preference, but the adjectives with abstract concepts could not rely on visual cues and neither pure static forms. To sum up, photograph could improve the noun transparency/preference and illustration could raise action transparency/preference. Moreover, static status was applied to vocabularies contained large abstract concepts. The analysis showed that static status with supplement line form was relevant to action with visible movement traces while animation form could enhance the transparency in core vocabularies featuring more conditions and positive concepts.