People with different positions have different views on what justice is. Plato, an ancient Greek philosopher, believed that what people should do according to their own level is justice; Christian ethicists believe that it is just that the body should obey the soul. Marxist ethics believes that the objective standard of justice mainly lies in whether its behavior meets the requirements of social development and the interests of the broad masses. We are followers of Marxism, and we take the road of Marxism. The justice we call for in our hearts is fairness, justice, honesty and justice, which is popular in the world and the truth closely related to people's interests. When people evaluate whether a law meets the standard of justice (legitimacy), it is often based on whether the law can adjust social relations to satisfy all members of society. However, in fact, it is impossible for a law to meet the needs of every member of society. It can be said that everyone's needs are inconsistent, and conflicts between them are inevitable. Those social relations and social order regulated by just laws can only be recognized and satisfied by most members of society, so the law is the embodiment of the people's will. The law needs to be tested in all aspects. When people seek legal help and punish criminals by law, whether fairness is maintained and justice is done is the criterion of legal justice (legitimacy) and the soil on which law depends. Only when the law is based on justice can the concept of justice be sublimated on the basis of law.