The point of view for this story is from Sarty, a ten year old boy, for much of the story. Occasionally, Faulkner breaks this perspective and uses an omniscient narrator.
Faulkner was a fan of perspectivism, which is the telling of a story from a particular point of view or views. This story in particular is fairly traditional because the reader is given only Sarty's perspective for most of the story. Faulkner has written stories that employ a variety of narrators, such as The Sound and the Fury.
The point of view in Faulkner's "Barn Burning" is one of a limited omniscient narrator. The narrator is not a real live person in the story but rather a nonparticipant who can see into Sarty's head. Faulkner does this so that he can build up to the climax of the story giving only the details he thinks are crucile for the reader to know without giving away too much of Sarty's thoughts. You will notice that at times the narrator says things that Sarty himself doesn't know or even what Sarty would think if only he were older.