Betty Talmadge, 54, the former wife of Sen. Herman E. Talmadge (D-Ga.), formally announced her candidacy yesterday to succeed retiring Rep. John J. Flynt Jr. (D-Ga.), who has represented a middle Georgia congressional district for 24 years.

Nervously reading her prepared statement in a motel conference room near the Atlanta airport, Talmadge sounded a theme of fiscal conservation for government similar to the one she heard from her husband for the 35 years she was the wife of the senator.

"One of the most crippling causes (of inflation) is excessive government spending, whether such spending is for foreign affairs abroad or domestic programs," she said.

Talmadge made it clear that she views her candidacy in the Democratic Party primary of Aug. 8 as serious and no question exists that her name recognition in the district exceeds the other announced candidates, including two state senators and a college professor.

"She would be a formidable candidate, but it's going to depend on Sen. Talmadge,'" said Thomas B. Murphy, speaker of the Georgia House, who is not particularly close to the senator. "If he puts out the bad word on her, it will be tough. If he stays out of it, she's got a good chance.

"But I'm telling you if he spreads the word among his friends in the 6th District that he don't want her in that seat, then she's got big troubles."

A spokesman for Talmadge said the senator's reaction to his ex-wife's announcement was "No comment."

Last year, the senator filed for divorce, claiming that his marriage was "irretrievably broken," a ground in Georgia's "no-fault" divorce law. Betty Talmadge counterfiled, claiming that the senator was guilty of "cruel treatment" and "habitual intoxication."

They were divorced, but settlement of property, estimated at more than $1 million, continues to be disputed in court. The next round will be a hearing before the Supreme Court of Georgia.

In her announcement, Talmadge emphasized her considerable success in business, particularly food production. She managed the Talmadge ham operation for many years.