Huang-Lao thought was a belief that flourished during the late Warring States 戰國 (5th cent.-221 BCE) and the Han 漢 (206 BCE-220 CE) periods. It is named after the two key figures cherished by the adherents, namely the "Yellow Emperor" Huangdi 黃帝 and Laozi 老子.
The Yellow Emperor was a mythological ruler of antiquity and was venerated as a demigod with a strong sense for inventions and supernatural forces. He is also revered as the ancestor of the Huaxia people 華夏, the Chinese. The appraisal (zan 贊) of the biography of Yue Yi 樂毅 in the official dynastic history Shiji 史記 lists several teachers of Huang-Lao thought: Heshang Zhangren 河上丈人, Master An Qi 安期生, Master Yue Jia 樂瑕公, Master Yue Chen 樂臣公, and Master Shan 善公. The Shiji also called legalist philosophers like Han Fei 韓非 (c. 281-233) or Jixia academicians 稷下 like Shen Dao 慎到 (395-315), Tian Pian 田騈, Huan Yuan 環淵 or Jiezi 接子 adherents of Huang-Lao thought.
Many important politicians and thinkers of the Former Han period 前漢 (206 BCE-8 CE) were adherents of the Huang-Lao religion, like Xiao He 蕭何 (257-193), Cao Shen 曹參 (d. 190), Chen Ping 陳平 (d. 178), Sima Jizhu 司馬季主, or Empress Dowager Dou 竇太后 (200-135). There were also Master An Qiu 安丘生, Master Wang 王生 and Master Huang 黃生.
The imperial bibliography Yiwen zhi 藝文志 of the dynastic history Hanshu 漢書 mentions 21 books on Huang-Lao thought. Except for the medical classic Huangdi neijing 黃帝內經, all are lost. In 1973, some Huang-Lao books on silk inscriptions were discovered in the early Former-Han-period tomb of Mawangdui 馬王堆, Hunan: the so-called B version of the Laozi (Laozi yi ben 老子乙本), Jingfa 經法 "The constancy of laws", Shidajing 十大經 "The ten great classics", Cheng 稱 "Aphorisms" and Daoyuan 道原 "On Dao the fundamental". These are known as the "Yellow Emperor's four books" (Huangdi sijing 黃帝四經) or as Huang-Lao boshu 黃老帛書 "The silk books of Huang-Lao thought".
The content of Huang-Lao philosophy is derived from Daoist and legalist sources. The legalist "standard" or "law" (fa 法) is derived from the natural "Way" (dao 道). Penal law (xing 刑) and virtuous government (de 德) play an essential role in expressing authority and benevolence by a superior. There are also traces of Yin-Yang theory (accordance with the seasons, complementary pairs of qualities), Confucian (social order), and Mohist (sparingness in state expenditure) thought and some influences of the dialecticians (identity of designation and reality).
The natural Way is considered an objective principle that exists throughout the universe, governing Heaven, Earth, and all beings, including humanity and the structure of human society. Although it is neither visible nor possesses extension, the Way influences all aspects of life. In human society, the Dao is referred to as li 理, meaning "natural order"; in politics, it is termed fa, meaning "law". The unity of action with the Way will lead to harmony with the universe. Such a condition will unite the greatest and the smallest, the peak and the decline of life and state. A ruler must seek unity with the Dao and govern with reward (shang 賞) and punishment (fa 罰). His ministers must fulfill the responsibilities of their posts to ensure there are no contradictions between designation (ming 名) and reality (shi 實). Such a state will exist in a pure and tranquil (qingjing 清靜) condition, allowing the lord to rule even through non-action (wuwei er zhi 無為而治) and to comfortably "fold his hands and let his gowns drop" (chuigong 垂拱).
Punishment must be applied without exaggeration, and the population must not be burdened with high taxes; laws should, as far as possible, remain unchanged (yinxun 因循 "continuance"). Once the empire is united under a central government, peace and virtue must prevail, and strife must be avoided (hao de bu zheng 好德不爭). Historians interpret the rule of the early Han emperors Wen 漢文帝 (r. 180-157) and Jing 漢景帝 (r. 157-141) as being guided by these ideals, leading them to refer to the era as the Golden Age of Wen and Jing (Wen Jing zhi zhi 文景之治), when relief was brought to the people and the national economy was able to recover.
During the Later Han period 後漢 (25-220 CE), Huang-Lao thought was quasi invaded by the belief in immortals and experienced a more religious aspect with incantations, the exorcism of ghosts, sacrifices to spirits and the belief in omina and portents as expressed in the apocryphal classics (chenwei 讖緯) and the talismanic (fulu 符箓) writings of Daoism. Magicians (fangshi 方士) played an important role in everyday life. The Huang-Lao thought merged at that time with the early Daoist schools.