Is this external DVD drive Mac compatible?
The best way to know for sure is to check for yourself. If you have access to an Apple store, you can just bring it in and try it on any of their Macs there. (All Macs have the same standardized OS with the same drivers available)

That being said, the answer is most likely yes. Generic USB devices like this are typically fairly standard, and usually have great plug and play support on Macs.