Inquiry method of household registration number: 1. Need to go to the public security organ where the household registration is located. Only individuals and household registration departments can find the account number of the household registration book, and citizens can check their own original household registration book to find the household registration book. 2. Except for the people's police of public security organs or personnel engaged in related work who can inquire in the public security population information system, no other unit or individual has the right to log in to the population information system to inquire about personal data. The household registration book is an important document of China citizens, which is jointly produced by the people of China and the Ministry of Public Security. It is used to register the name, place of origin, date of birth, specific professional title, occupation, etc. Going to school, getting married, getting a passport, and doing many important things need to be used. China's household registration management regulations stipulate that the basic tasks of household registration management are: maintaining social order, protecting citizens' rights and interests, and serving socialist construction, which is also the purpose and function of China's household registration system. Household registration can provide basic population data. For example, how many people there are, how many urban and rural areas are distributed, how many elderly people there are, how many laborers there are, how many school-age people there are, how many infants and young children there are, how many industries there are, how many educational levels there are, how many marital status there are, and so on. Only in this way can we make scientific and reasonable plans for national economic and social development, make overall arrangements for material and cultural production, and promote the sustained and stable development of social economy.