《The night of railway in galaxy》was Miyazawa Kenji’s unfinished work and the writing time was unknown. The first draft of this work was finished in the year of 1924, but he modified and edited the work constantly for about ten years. The posthumous work was created after four-time considerable modification. This work had never published before his death, but after Kenji died, Kenji’s works were drawn much attention and liked by a great number of readers. His passionate and imaginary idealism, unique sense of universe and his mercy enable him to gain high praise.It is know that《The night of railway in galaxy》is about lonely youngsters - Jyobanni and Kamupanerura’s amazing railway trip in galaxy. In this work, Miyazawa Kenji released self-sacrifice and imagination weaved by lonely soul from the restriction of society, space and time, presenting the spectacular world in galaxy.Therefore, the researches on《The night of railway in galaxy》have been conducted a lot until now. We can categorize these research findings in accordance with the preceding research as three types: the first one was started from the author’s life experience to analyze his writing intention; the second type was to explore the real meaning of this work by analyzing the main characters and key words in each situation; the third one was to explore the author’s creation features from the constant modification from the first draft to the final one. However, the research is far from enough only from three perspectives. In this thesis, based on the final draft (the fourth), the author proposed to analyze Kenji’s unique imaginary concept in terms of content and form of expression. In terms of content, besides the traditional perspectives such as space, characters, the author introduced the new viewpoint of“hint”to analyze children’s imaginary literature. The author intended to see how the hint had been left in real world and how it was presented perfectly in imaginary world. Therefore, in this thesis, some theories about“hint”will be adopted based on literature research.In terms of the form of expression, the author used the techniques of“symbolization”and“absurdity”to analyze this work. Although in the previous research, the technique of symbolization has been used to explore this work, it is seldom mentioned in the journey of“real happiness”. Moreover, to analyze this work from the perspective of“absurdity”is another new viewpoint of this thesis. Through the absurd imagination and humorous language, we can find out the hidden realistic logic which aimed to criticize social mechanism. The absurdity in fairy tale can not only reveal a free attitude, but also fulfill children’s curiosity and reading psychology.To sum up, the independent research on imaginary concept in this thesis will be beneficial to the thorough analysis of Miyazawa Kenji’s deep mind as well as the understanding of his religious view, recognition of space and view of universe.