which one is better?

“the art of driving or” “driving art”? if one of them is better than the other, please tell me why?

Do you mean “skill in operating a car”? If so, “the art of driving” is usually better. While there may be specific contexts in which “driving art” would work, generally it seems likely to confuse or be misunderstood. It may not be clear that “art” means “skill”, or that “driving” means “operating a car”.

[Edited] My response above simply compares the two options you asked about, but in many everyday situations, something like “driving skill(s)” would be more usual. “art” makes the process sound grander and more cultured.