Generally, credit card limit will not be accumulated. Multiple credit card lines of the same bank can generally share credit lines. The amount of each credit card is actually different, but there will be a maximum limit and it will also be limited by the sharing limit.

For example, suppose you have three credit cards, one 10000, one 20000 and one 30000. These three cards share a quota of 30,000. If you want to get a higher quota, you must apply for a credit card from a different bank.