Aphasic patients have language difficulties, but clinical speech-language therapists frequently use individual therapy rather than group therapy in treatment sessions for patients with aphasia. The purpose of this study was to design a group treatment program for aphasia patients and to understand its impact on aphasic participants' language abilities. The participants were five adults with chronic non-fluent aphasia. The group treatment program consisted of two 3-hour sessions per week for 20 weeks, with each participant receiving a total of 120 hour of group treatment. Five data-gathering tools were used to assess the effectiveness of group treatment: the Concise Chinese Aphasia Test (CCAT), the Aphasia Group Conversational Competence Rating Scale (AGCCRS), the Functional Communication Activities Scale (FCAS), the World Health Organization Quality of Life Questionnaire (WHOQLQ)-Taiwan Concise Edition, and a satisfaction questionnaire. In our results, the CCAT and WHOQLQ showed no significant changes. However, the AGCCRS showed a significant increase in conversational abilities. The FCAS also showed a significant increase in the social communication field. Overall, all the participants reported being very satisfied with the treatment. In addition, the satisfaction of their families was also high. According to the results of this study, the group treatment program can contribute to increased group conversation and social communication competence for adult patients with chronic aphasia.