1. Appearance distinction: the second generation has the words "social security card" on the front, and the card number, personal identity information and card issuer on the back. The third generation has the words "social security card" and "PBOC" on the front, and personal identity information on the back.

2. Chip differentiation: The second-generation chip mainly stores electronic medical insurance voucher information, while the third-generation chip supports the storage of personal basic information and various other service information.

3. Use function distinction: the second generation is mainly used for medical insurance and retirement insurance, and the third generation provides more scene payment functions.