Sunday's race will be the third of the 10 in the series that will determine this year's Sprint Cup champion.
Earnhardt stands in 11th place in the championship chase heading into Sunday's race, in which he will start on the pole thanks to a qualifying lap of 161.849 miles per hour. It was his second pole of the season and the 13th of his career.
Earnhardt has not won in 47 races and his only win in Dover came a dozen years ago.
Matt Kenseth, who has moved into the championship lead thanks to winning the first two playoff races, qualified second at 161.805 mph.