This paper studies the history of anatomy in ancient Alexandria. Various testimonies report that two Alexandrian physicians, Herophilus and Erasistratus, dissected and vivisected human. But some scholars have objected to the tradition for various reasons. So, I try to examine the meaning of the tradition and to justify it in the face of some objections, then try to understand how dissection came to be performed in Alexandria. But my main concern is to show the character of the research, that is Alexandrian anatomy. For the purpose, I discuss its aims and motives in the social and historical background. The value of a tradition can only be judged through a historical understanding of the time from which it delivered. In conclusion, I admit that Ptolemaic patronage was the most important incentive for the ancient anatomy. But this was only a necessary condition. Alexandrian anatomists' motives were greatly influenced by the contemporary natural philosophy, especially Aristotelian biology. And interestingly, Erasistratus shows some mechanical world-views, which can be compared to the stoic macrocosm-microcosm analogy.