A 34-year-old Canberra man has been sentenced to more than nine years' jail for incest after offences against his stepdaughter.

The man pleaded guilty to 10 charges, including incest and several charges of committing an act of indecency.

The offences were made worse by the fact the man, who had lived with the victim's mother and her four children, was regarded as a trusted father-figure by the family, Justice John Burns told the ACT Supreme Court.

Justice Burns said that while the man had demonstrated a degree of remorse, his conduct had been a gross breach of trust for the victim and her mother.

He said the man had abused his authority over the child.

Justice Burns said another aggravating factor was that the girl suffered an intellectual disability.

The offences happened in 2012 and 2013 when the victim was 10 or 11 years old.

The man had committed several of the offences after making the girl stay home from school with him.

The court heard some offences happened in a car and others in a spa bath in the family home.

The man had also given the young girl a vibrator, which police found in the car during a search.

Justice Burns said the man's culpability was high.

"You set about corrupting this child for your own selfish purposes," he said.

The man had denied he was sexually attracted to the child and said he was only trying to teach her about sex, and he did some of the things so as to not disappoint her.

But Justice Burns said the man had tried to minimise his responsibility.

"I am satisfied you were sexually attracted to the victim," he said.

"You used her for your own sexual gratification."

The man has been sentenced to nine years and three months in jail.

He was charged with six counts of committing an act of indecency, and four of incest.

The man will not be eligible for parole until 2019.