In the face of the city‐state crisis, Aristotle put forward the idea of building an ideal city-state, and the key to building an ideal city‐state is to build the ideal citizens in the city-state. Therefore, he put forward the idea of citizen rationality, which aims to improve the citizen consciousness of the city‐state citizens, so as to promote the citizens to actively participate in the city‐state affairs and bear the corresponding obligations and responsibilities. In fact, the discussion of citizen rationality is not only stopped here. Based on the consideration of realistic politics, citizen rationality is the conscious reflection of modern social members on their citizenship and its value, which mainly includes citizens' consciousness of subject, rights, responsibility and rational participation. This also further illustrates the importance of civic rationality. In a democratic society, civic rationality will affect citizens' subjective consciousness, participation consciousness and even cooperation ability, which enables citizens with certain literacy to better solve and deal with corresponding differences and contradictions, and better promote the common interests of civic groups. Citizen rationality constitutes the psychological basis of modern democratic politics, which is the cognition and emotion formed by the internalization of democratic system idea into citizens political psychology. Citizen rationality can make citizen participation more in line with public interests and public rationality, and promote the maximization of the interests of citizen groups, so as to promote the construction of democracy, good governance and harmonious government.