Abstract: As a classic text, Regret for the Past can be interpreted in multiple ways. Previous studies on the theme of female liberation and the philosophical discussion on " emptiness” and " reality” have been explored in depth. This article begins with a famous explanation by Zhou Zuoren, which claimed that Regret for the Past is " mouning the the break-up of their brotherhood with the love and death between men and women”. The analysis of the metaphor for brotherhood is neither trying to verify Zhou Zuoren’s assumption nor to match the figures with Zhou brothers, but to discuss their ideological differences and outlooks on life through this metaphor. In Regret for the Past, Lu Xun reflected on the old ideas emerged on the young generation and the issue of " new way of living”, and again raised the necessity of " ideological revolution” and actions at the present. In a way, the metaphor for brotherhood in Regret for the Past has referred to two different paths of intellectuals in 1920s.