i drive my brothers car hit someone,and i dont have insurance,what i can do?

The question is did your brother have insurance on the car you were driving. If he did, and you are a permissive user and not an excluded driver on the policy, you are covered under his policy. If he did not have insurance on the car, both you and he could be personally liable for any damages caused by your negligence, although his liability may be limited by California Vehicle Code Section 17150.

If your brother had insurance and you were driving with his permission, then you are covered by his policy. If he was uninsured, you and your brother may be liable to the person you hit. They may have uninsured motorist coverage, in which case their insurance carrier will pay their damages and then later try to collect against you.

The owner of the car should have had insurance, which would cover you. It should be reported to his insurance company.