This article aims to analyze the philosophical themes of hayy b. Yaq Zan, which is considered the first Arabic philosophical novel written by Ibn Tufail(1105~1185), a Muslim philosopher and physician in early 12th century Islamic Spain. hayy b. Yaq Zan occupies an important position in the world history of philosophy and literature, because it is one of the first works that used a fictional narrative for the treatment of philosophical themes. hayy b. Yaq Zan tells the story of a man, a self-taught philosopher of perfect intelligence, growing up on an equatorial island without parents, language or culture, who discovers for himself all phases of knowledge, from the technical and physical to the spiritual truths underlying scriptural religions. A significant feature of this philosophical novel is the attempt to show that humans are endowed with reason and free will. In this novel, hayy, who lives on a desert island, has no family, no religion, no history and no religion. In spite of these circumstances, he learns how to be self-sufficient. Reason, which has been bestowed upon him, helps him to learn everything himself. Finally hayy comes to attain metaphysical truth including the heavenly bodies and the Mover of the Universe, without any help of teachers, prophets and religious institutions. On the other hand, this novel makes two attempts to make the harmony between philosophy and religion. Firstly, it deals with the problem of the eternity or creation of the world. For centuries, Muslim theologians such as al-Ghazali criticised philosophers of insisting on the eternity of the world. In this novel, hayy tries to settle this problem by saying that the eternity of the world dose not deny the existence of the creator. Secondly, it tries to show that the teachings of reason and revelation are ultimately the same. In the latter part of the novel, hayy learns to speak and knows the religious teaching of the human society from his friend Asal, who visited the island. Through conversations both men realized that the teachings of prophets are mere representations in sensible terms of the spiritual realties hayy perceived on his own. Ibn Tufail`s Hayy b. Yaq Zan had a significant influence on Arabic literature and European literature after it was translated in the 15th century into Latin and then into several other European languages. In the 13th century, hayy b. Yaq Zan inspired Ibn al-Nafis to write the first theological novel, Al-Risalah al-Kamiliyyah fil Sira al-Nabawiyyah. This novel was written as a critical response to hayy b. Yaqzan. In 1719, one of the English translations of hayy b. Yaq zan inspired Daniel Defoe to write Robinson Crusoe, which was also set on a deserted island and was regarded as one of the first novels in English.