本文首先比較了《盛夏光年》電影與劇本之間的差異；其次，透過佛洛伊德精神分析方法，檢視《盛夏光年》裡，潛藏於電影和劇本中的性欲暗示，及兩位男主角余守恆與康正行的潛意識流動、創傷經驗、自戀情結和自我認同等問題。最後，再以拉岡的「鏡像理論」，通過鏡像的分裂與完整，深入細究兩位男主角彼此分裂而互補之微妙關係。本文在重新解讀劇本與影像後，期望以精神分析理論為一全新視角，微觀人物在潛意識、創傷、自戀和自我認同等命題上，複雜的心理變化與二人對情愛的抉擇（抑或是自我性取向的抉擇），進而擴大了《盛夏光年》整體故事之深度與格局

First, the study compares the differences between the film and the original script of ＂Eternal Summer＂; second, it reviews the sexual hints hidden in both film and original script of ＂Eternal Summer＂, as well as problems of two main male characters, Shane YU ( 余守恆) and Jonathan Kang ( 康正行), including their stream of sub-consciousness, traumatic experience, narcissism and self-identity. The last but not the least, the ＂mirror phase＂ proposed by Jacques Lacan is introduced to analyze deeply the subtle relationship, separated and complementary at the same time, between these two characters via divided and complete mirror image. After reinterpreting the original script and the image, the study looks forward to analyzing ＂Eternal Summer＂ by a whole new perspective of psychoanalysis and observing the complicated psychological change and love choices (or the choice of sexuality) of two characters when it comes to sub-consciousness, trauma, narcissism and self-identity, which make the story deeper and more meaningful and broaden the horizon of the audience