思想因演進而展現不同的風貌，各代皆有其特色，我們也很習慣的以斷代為思想的分段，而有先秦諸子學、兩漢經學、魏晉玄學……等概括的稱謂，這樣的概括凸顯時代的特色，當然有其代表性，不過，也有相當的侷限，例如，經學顯然不能涵攝兩漢學術；再者，各朝代不同形貌的思想是如何轉變的，也不能反映在這種概括中。 本文就針對秦漢之際思想的發展，從環境的變遷、知識份子的心態的轉變、思想的演進等方面著手，提出「諸子百家混融」、「大一統思潮」、「儒者的崇儒自覺」、「黃老思想盛行」、「法家思想的潛藏」、「陰陽家思想瀰漫」六點，說明秦漢之際的思想實況，也試著說明先秦諸子學說如何逐漸演變為兩漢思想。

　　　　　Thought shows different features through evolution. Each Dynasty has its own characteristics. We tend to divide schools of thought according to the chronological order of dynasties, and that is how we name schools of thought: the various schools of Pre-Chin period, the classics of Han Dynasty, and metaphysics of Wei-Chin Dynasty. Such a general division is convenient, but there is a limitation. For instance, the classics do not cover all the schools of the Han Dynasty, and the development of various thoughts in each dynasty cannot be reflected in this kind of division. Based on the change of environment, the transition of the intelligentsia's mind and the evolution of thought, the study aims at researching the development of thought in the transition period between the Chin and Han dynasties. Six key characteristics are presented to depict the various schools of thought and their exponents during the period from Pre-Chin to the early years of the Han Dynasty: unification philosophy, upholding of the Confucianist consciousness, the prevalence of the philosophy of Lao-zi, the submersion of the judicial school of thought, and the pervasion of the thought of Yin/Yang (the concept of the five elements). These are explained in the paper to give a picture of the thought between the Chin Dynasty and Han Dynasty and of the process in which various schools of Pre-Chin times evolved into the thought of Han Dynasty.