i was wondering if they can get all the pet or it depend on the race

Mounts or pets ?? Mounts are deathhorses

http://www.wowwiki.com/Mount

Deathchargers are the mounts of death knights

Death Knights all get the same Acherus Deathcharger no matter what the race. You can also still get your race's mounts without having to be exalted, but you still have to be exalted with the other races of your faction to obtain their mounts.