The present study analyzed Houshang Golshiri’s discourse style in his short story of "Dehliz (=Atrium)", and the use of language in this text considering systemic functional grammar. The main question in this paper is: To what extent have the linguistic elements of the story been successful in representing political and social realities? In order to answer this question, the authors examined the text of the story according to the metafunctions to reveal how Golshiri's mental images of reality were coded in the language of his writing. In this story, 239 processes have been found and examined based on Halliday’s model, but due to limitations, only a few examples of each process are mentioned. The method of this research is descriptive-analytical. In this way, all verbs in the text have been extracted and the frequencies of the processes were identified. Then they were grouped and analyzed according to Halliday’s method. Among the three metafunctions, the focus of this article is on ideational and textual metafunctions. The findings demonstrate that material, behavioral and relational processes have mostly been applied and existential, mental and verbal processes have rarely been used. The high frequency of the material process in the story reflects its relevance to the historical context of Golshiri-era society, which coincided with the growth of capitalistic thought and the development of industry in Iran. Also, it shows that in his realistic discourse, the writer seeks to represent his attitude toward the political situation of the society. Compared to the material processes, mental processes have less frequency. It indicates that the writer has seldom involved his own and his discourse addressees’ feelings, and mental characteristics in the discourse of this short story. The processes and texture of the text fit together. The high frequency of use of past tense is a factor that has increased the degree of certainty in discourse.