1. Check account book or ID card: The simplest and most direct way is to check my account book or ID card, which will have my own ID number on it.

2. Log on to the online information inquiry website: If you don't have your ID card and household registration book with you, but you have used your ID card to purchase tickets online, you can log on to the relevant website to inquire the ID number.

3. Ask the household registration department for help: If all relevant household registration materials are lost and there is no online ticket, you can only ask the household registration department for help. I can go directly to the neighborhood Committee where my household registration is located, and quote my name, address and other information, so that the household registration management department of the village Committee or community neighborhood Committee can help me check, or I can go directly to the public security department for consultation, explain my situation and ask for help.

4, through the national citizen ID number query service center.

The main functions of the ID number are:

1. Identification: The ID number is a unique and life-long valid identity code for citizens, which can accurately reflect the basic information of individuals, such as date of birth and address.

2. Online verification: Through the ID number, online verification can be conducted in public security, banks and other departments to confirm whether personal identity information is true and valid.

3. Handling documents and affairs: When handling various documents and affairs, you need to provide your ID number to verify your identity, such as handling mobile phone cards, bank cards, driver's licenses, passports, etc.

4. Legal liability: In terms of legal liability, the ID number is an important basis for determining personal identity, such as criminal record and debt collection.

5. Social management: in situations involving social management, such as traffic management and tax declaration. You also need to use your ID number for information collection and registration.

To sum up, the ID number is an important proof and basis for citizens to participate in social life, and it is also one of the important means for the state to carry out social management. Therefore, it is very important to protect the security and privacy of personal ID number.

Legal basis:

People's Republic of China (PRC) Identity Card Law

Article 12

The public security organ shall, in accordance with the provisions, apply for the collection, renewal and replacement of resident identity cards. The public security organ shall issue resident identity cards within 60 days from the date when citizens submit the application registration form for resident identity cards. In areas with inconvenient transportation, the processing time may be appropriately extended, but the extension time shall not exceed thirty days.

Citizens who urgently need to use their resident identity cards during the application, renewal and replacement of their resident identity cards may apply for temporary resident identity cards, and the public security organs shall handle them in a timely manner in accordance with regulations. The specific measures shall be formulated by the public security department of the State Council.