The "eclecticism" advocated by Saint -Saens in his piano compositions reflects both his adherence to classical techniques and his integration of contemporary trends, enabling his works to directly express the unique humanistic sentiments of French music. From an interdisciplinary perspective, this article takes Allegro Appassionato, Op. 70, as its focus, analyzing its form and connotation through specific manifestations of creative thought and artistic value. The aim is to uncover the causes and developmental trajectory of the concept of "eclecticism". As a philosophical idea, "eclecticism" intertwines philosophical thinking and musical ideals, embodying "artistic synesthesia" as a universally interconnected whole. This research provides novel insights and value references for the exploration of piano composition styles, offering a fresh perspective for the innovative transformation and development of the musical arts.