This paper will examine the development of the Modern Taiwanese poems. In particular, the paper will focus on identities of the immigrants who came from the Mainland to Taiwan. This study will also invite an exploration of the Taiwanese history colored by immigration, which is distinguished from the history of the Mainland. Therefore, I will study an overall Taiwanese history and the development process of the Modern Taiwanese poems first, and then will introduce and analyze nostalgic poems written by immigrants who came from the Mainland since 1949. Mostly, these poems were written during the period from the mid 1950s to the 1970s and made great contributions to the development of Modern Taiwanese poetry. Most poets came to Taiwan following the Nationalist Chinese Army led by General Chiang Kai-Shek in order to flee from the political chaos in the Mainland. They also went to the U.S. for their advanced study. Their migration experiences not only enriched their feelings particularly nostalgia for the homeland as diasporas but also had great influences in forming their identities. They missed lives in and culture of the Mainland when they were in Taiwan, but they also suffered from nostalgia for Taiwan when they were in the U.S. Their sorrow and solitude are fully melted in their poems. Hence, I try to understand Taiwanese cultural identity as diasporas further by studying these nostalgia poems, and this study will help to perceive the peculiarity of the Taiwanese history and culture.