This paper explores the culture of tortoise worship in the world, and particularly researches on the reason why the culture of tortoise-worship was produced in ancient China. The answer is of the follows: Tortoise has a image of both the Heaven, Earth and Man; the clan of Huangdi Emperor had a totem of tortoise; the origin of divinatory symbols of Yi is of the veins of abdominal shell of tortoise; tortoise has a long life and great vitality; tortoise was one of the four sacred animals. Buildings, villages, towns and cities with the shape of turtle are explored and their cultural connotation is discussed.