I am 21 years old and my boyfriend is 15. His mom and dad approves. But my is try to get my boyfriend take from his parents because I am dating him.

Your last sentence doesn't make sense: "But my is try to get my boyfriend take from his parents because I am dating him."

Are you saying your parents have a problem with this?
I have no idea what you mean, it makes no sense. It may be legal if his parents are OK with it, although I don't know what parent of a 15 year old would be OK with their kid dating a 21 year old.
I also don't know why a 21 year old female would be interested in a 15 year old male.
That is funky.

There are no laws that govern dating. However, 15 is below the age of consent in most areas. So if you were caught doing any sexual activity with him, you could be prosecuted for that, whether the parents agreed to your dating or not.

Other than that, as long as the parents are aware and do not object to your dating, no laws are being broken. However, I question what ANY 21 yr old would see in a 15 yr old. Especially when the 21 yr old is female and the 15 yr old is male.