Antigone is most definitely filled with allusions to Greek mythology. Since an allusion is a moment when one author refers to a piece of literature, and since mythology stories, especially about the gods, were written down by the Greeks, any time we see the name of a god mentioned, the reference is a mythology allusion. There are far too many to go over a lot of them, but a below are a couple to help get you started.
One allusion to Greek mythology can be seen in the Chorus's account of the war between Polynices and Eteocles. The Chorus describes Polynices as an eagle that flew into the land, carrying armor, as we see in the lines:
... like a sharply crying
eagle flying into our land,
covered with a wing white as snow,
descending with many shields
and crested with horse-hair. (111-15)
This reference to an eagle is actually an allusion to Zeus's eagle called the aetos dios. The eagle was known to help Zeus in war as well as in love. The eagle carried the thunderbolts that Zeus threw at his enemies (Atsma, "Aetos Dios"; Ridpath, "Aquila"). Hence, since Polynices is being described as a destructive eagle, this is clearly an allusion to the aetos dios.
The Chorus also uses a second allusion to describe the war by referring to Hephaestus, as we see in the lines, "...before [Polynices'] jaws were filled with our blood / or Hephaestus' torches could take our crown of towers" (120-21). According to Greek mythology, Hephaestus is the god of fire and uses a volcano to forge armor for the gods ("Hephaestus"). Since he forges armor, using Hephaestus as an allusion is an excellent way to describe the war.