This article provides an existentialist reading of Liu Cixin’s novel The Three-Body Problem (Santi). Luo Ji, with the chance/miracle of Trisolaran invasion, got rid of the unreal status and became the self-conscious existence and the hero who protected the mankind by his decisiveness and responsibilities. However, he gained terror and hostility from human. Eventually, human civilization was extinct because of the rejection to the heroes. The Three-Body Problem showed Liu Cixin’s endeavor to revive heroism in the contexts of China and the world, but also represented the writer’s confusion as a symptom of the era when he was dealing with the ideological theme of hero and the common people.