Kathleen Kane, a Democrat elected in November, said the investigation would focus on why it took three years before criminal charges were brought against former Penn State assistant football coach Jerry Sandusky, The New York Times reported.
She said the special prosecutor would be named soon.
Kane hinted during an interview with the Times that when he was attorney, Corbett, a Republican, dragged the investigation of the longtime coach while campaigning for governor.
Corbett, who was elected governor in 2010, rejected the suggestion that he slow-walked the case.
Sandusky was convicted last year of molesting eight boys. In January, Corbett sued to lift the stiff NCAA sanctions imposed on Penn State because of the episode
Corbett declined to be interviewed, the Times said. He has denied delaying or mishandling the investigation.
"The governor is happy to talk to anybody about it, including Kathleen Kane," his spokesman, Kevin Harley, said. "The proof is the conviction of Jerry Sandusky on 45 of 48 counts, and he will spend the rest of his life in jail because of the work of the men and women in the attorney general's office and the state police."
Kane, a former county prosecutor who specialized in child sex abuse cases, questioned why it took nearly three years to arrest Sandusky in late 2011 after Corbett, as attorney general, received a complaint against Sandusky in 2009.
"It's never taken me that long," Kane said. "I was on the campaign trail almost two years; I didn't go a single place without somebody asking me why it took so long."
Randy Feathers, who supervised investigating agents when Corbett was attorney general, said it took that long because "we felt like we had no shot" at a conviction with only one victim.
"You very rarely find a predator in those circumstances who only molested one kid," Feathers said. "Our job was to find those kids."
"Tom Corbett had nothing to do with slowing anything down," Feathers said.