Character is the foundation of life, drama and play. And presenting topics in the form of drama and by designing believable characters can act more effectively in delivering the concept to the audience. Since radio is an imaginative media with the power of influencing more and faster than other media, this study has been devoted to the study and explanation of special rules for the credibility of the personality that is in line with the limitations and privileges of this medium , and try to make a deeper link between radio plays and audience. In this study, we have used library research and qualitative content analysis. To this end, 5 radio shows have been selected by targeted sampling method, and the main characters of these plays are divided into four main categories ( Introspection / Extroversion, Sensory / Intuitive, Thought / Emotional, Judicial / Receiving) ,according to the theoretical framework (Myers-Briggs theory), and have been analyzed. Findings of the research show that most characters are placed in two categories of conceptual mood and idealistic mood, which are contradictory to external reality and what is observed in society, and this causes the characters to be discarded from reality and as a result their unreliability will be addressed to the audience. Thus, according to the findings of the research, it is concluded that the correct recognition of the character and its adaptation to actual characters and what is going on in real life, could be effective in creating believable personalities.