本文主要对柏拉图《理想国》中的核心政治思想——“哲学王治”进行探讨。第一部分理想的提出。主要讨论了时代背景和自身经历对柏拉图提出哲学王治理想的影响。第二部分理想的设计。分析了柏拉图对当时希腊社会流行的正义观的批驳，阐释了柏拉图的正义观和哲学王治的正义性，指出哲学王治的本质就是哲学与政治的结合——作为哲学家的智慧和作为政治家的责任。第三部分理想的实现。通过洞穴喻来阐释柏拉图为实现哲学王治理想而进行的努力：走出洞穴——哲学王的选择与教育；返回洞穴——哲学王的牺牲与责任。并分析了理想城邦中的配套政策。第四部分理想的退守。主要讨论了柏拉图晚年基于现实而对哲学王治的理想进行的修正，提出了作为次好政治的法治，但他始终强调最好的政治是哲学王治。结语中讨论了《理想国》中法律的地位问题，并对柏拉图的哲学王治思想进行了总体评论。

This article mainly analyzes the core political thinking of Republic of Plato——the philosophy king governs.The first part inspects the statement of Plato's ideal. Mainly discusses the influence of the time background and own experience to Plato's propose of philosophy king governs.The second part inspects the ideal design. Analyze Plato's criticizes to the popular justice view of Greek society，explain Plato's justice view and the justness of the philosophy king governs. And point out that the essence of philosophy king governs is the union of the philosophy and the political——the wisdom as philosopher and the responsibility as statesman.The third part inspects ideal realization. Through the cavern analogies to explain Plato's endeavor to realize the philosophy king governs：Goes out the cavern——choice and education of the philosophy king；Returns to the cavern——sacrifice and responsibility of the philosophy king. Then analyze the related policy in Republic of Plato.The fourth part inspects ideal retreats. Mainly discusses Plato's revision of the philosophy king governs ideal based on the reality when he was old，then propose a second-good political——the government by law，but Plato always stresses that the best politics is the philosophy king governs.In the conclusion，I discuss the status of the law in Republic of Plato，and make the overall comments to Plato's philosophy king governs ideal.