Play is one of the important assets to mankind. The essence of play characteristic includes freedom, autonomy, creativity, beauty, and image that show human inner language experiences. Through Gundam’s interpretation of the theory of knowledge, the fusion of horizons, the article builds two levels of fusion of horizons models: the first-level fusion of horizons model between the player and the play field, and the second-level model between the player and the therapist or the trained companion. In the process of both fusion of horizons models, continuous closeness, and dialogue and circulation, play therapy has formed a meaningful healing ability with the stream of consciousness that exists in the present time along with the past and future experience streams, and achieves the purpose of play therapy goals. The therapist should handle cautiously during the process of play therapy. In order to make the therapy process meaningful, some suggestions from the article are summarized as follows: (1) The therapist should be careful not to put their own creativity and autonomy into the game too much, so that the players themselves can play freely and creativity won’t be suppressed in the game; (2) The unlimited degree of freedom in the game makes the vision of the therapist and the child merge into an invalid dialogue; (3) Allow players a space where errors and disarray are permissible ; (4) There is space for adventure in the game field, which could cultivate the player’s positive feeling, and the player might express the previously unknown emotional path from the game world. Through the fusion mechanism, the player could open himself and have the opportunity to experience the freedom and autonomy from the play, and touch the phenomenon of inner voice to explore the emotions of the player and see the self-appearance. There should be an open and reserved attitude towards the other innovated methods of game therapy in epistemology. In the existing play therapy framework, we should learn from knowledge models and think about whether we are accustomed to controlling this play therapy performance by the own way. The performer of therapy framework should humbly open up the many possibilities, methods and knowledge development of future game therapy.