On what date does ICBC withhold social security every month?

Generally, at the beginning of each month, the Social Security Association will send a payment notice to your company within 1-2 days, and then you will transfer the money to the social security account of ICBC. General social security society will deduct money before 10.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.