The word "legal system" has different uses and meanings at home and abroad, and usually has two meanings: ① refers to the laws and systems of the country. Laws include not only written laws in the form of normative documents such as the Constitution, laws and various regulations, but also unwritten laws such as customary laws and case laws recognized by state organs. System refers to various political, economic and cultural systems established according to law. China's ancient laws and regulations also belong to this category. (2) refers to a way in which the ruling class institutionalizes and legalizes state affairs in accordance with democratic principles and manages them strictly according to law. In this sense, the rule of law is closely related to democratic politics, that is, democracy is the premise of the rule of law, and the rule of law is the embodiment and guarantee of democracy. Only by institutionalizing and legalizing democracy and acting in strict accordance with the law can a country with normal legal order truly rule by law.

In Chinese ancient books, there is a system of "division of responsibilities and revision of laws" (Book of Rites and Monthly Orders), in which "legal system" refers to the establishment of a model system that people can follow. There is also the word "legal system" in the works of ancient legalists. "Guanzi Law Prohibition" wrote: "The rule of law is not discussed, and the people are not private." In the Book of Shang Jun, Jun Chen wrote: "People's livelihood has evil spirits, so it is forbidden to test." Han Fei also has the saying that "the rule of law is clear, and selfish interests are removed". All of these, although the "legal system" is linked with the rule of law, are not legal systems linked with democratic politics. The ancient "legal system" in China was, in the final analysis, just a kind of "monarchical power".

The legal system in the second sense, which is related to democratic politics, is consistent with the connotation of "rule of law" advocated by 17 and 18 century bourgeois enlightenment thinkers. For example, the British philosopher J. Locke believes that the government "should rule through the established laws promulgated by the government, which treat the rich and the poor, the powerful and the cultivators equally, and do not differ according to special circumstances" (two essays on government). American political critic T. Paine (1737 ~ 1809) also said: "In an authoritarian government, King China is the law. Similarly, in a free country, the law should be king "(common sense). Its core idea is to govern the country according to law, everyone is equal before the law, and any organization or individual is opposed to enjoying privileges outside the law. This proposition has played a great role in opposing feudal autocratic privileges and establishing and maintaining bourgeois democratic politics, which is of historical significance. However, the legal thoughts of bourgeois thinkers are obviously characterized by the supremacy of law, and it is impossible for capitalist countries to really implement the legal system. In order to pursue excess profits, exploit and oppress the proletariat and the broad masses of working people, they always rule by combining legal means with illegal means (see capitalist legal system).

The legal system is different from the capitalist legal system. This is an institutionalized, legal and strictly legal way to govern the country. Now, it is possible and necessary to establish this system in the form of law, and make this system and law have stability, continuity and great authority, so that there are laws to follow, laws to be observed, law enforcement to be strict, and offenders to be prosecuted, so as to effectively ensure that citizens are equal before the law, and no organization or individual is allowed to have privileges above the law.

The legal system is closely related to the legal order. Legal order is a kind of social order formed on the basis of strictly observing the law. It must be based on the implementation of the legal system, and the establishment of legal order is an important embodiment of the implementation of the legal system.