Taking the American literary giant Fitzgerald as the research object, this paper discusses in depth the formation and characteristics of his prose fiction genre and its specific performance in his masterpiece The Great Gatsby, and at the same time compares his writing style with that of Hemingway. By systematically sorting out the genre of prose fiction, this paper reveals its uniqueness and creative lineage and fills the gaps in the research in this field. In the close reading of The Great Gatsby, Fitzgerald’s prose language is placed at the core of characteristics and thematic expression, demonstrating the charm of language and the depth of narrative. The contrast with Hemingway’s style is not only reflected in various aspects of language, narrative technique and thematic treatment, but also highlights the unique position and contribution of the two writers in modernist literature. This paper not only focuses on Fitzgerald’s literary achievements, but also objectively explores the limitations of his creative career and the impact of his times, providing a new perspective for a comprehensive understanding of his literary legacy, and highlighting his creativity and lasting influence on modern American literature.