According to the Buddhist writing records, 2500 years ago when the Buddha alive, there was living a sort of animal named Dragon. Dragon was described as a type of creature of a half-men and a half-animal bearing assimilate to human being’s face and hands and feet, and have family life and society structure. Dragon could marry to human being and have they own offspring. The clan of Dragon were mainly scattered over an area of the north-west India, now known as at Pakistan nowadays. Because dragon were believed to be a type of longevity animal so that all of the Buddhist sacred scriptures, especially Mahāyāna-Sūtra had been placed in the clan of dragon’s custody to make sure of its safety and can be handed to next generations. According to authentic historic record that were compiled by Kumārajīva, Nagarjuna, the most important Mahāyāna scholar, had his first chance to get touch with Mahāyāna-Sūtra via one of the Mahāyāna disciple out of the clan of dragon, namely "Bodhisattva of A Big Dragon" , and what he had read all out of the dragon palace. So, the fact that whether the clan of dragon exist or not had direct connection with the important Mahāyāna scholar and the true exist Mahāyāna classics texts. Fortunately, the author had collected three wholesome of clay sculpture of the clan of dragon while the author making a academic visit to the northern part of Pakistan in 1995. Author had found another fragment of pottery unearthed from the northern part of Pakistan which belongs to part of the pottery holder of Buddhist scripture that was dating around the first century in the collection of The Swat Museum. By study of above mentioned 4 pieces of articles, author believes that the clan of dragon which must not only legendary tale.