He's been convicted of her manslaughter by a judge after a trial lasting nearly seven months.
Mr Pistorius shot through a bathroom door and said he only fired last year because he thought there was an intruder.
The judge has finished reading out her verdict after yesterday making it clear that the athlete wasn't guilty of murder.
During an adjournment soon after the verdict Pistorius held hands with his sister Aimee and prayed, according to reporters inside court.
High Court judge Thokozile Masipa had earlier said the 27-year-old Olympian was "negligent" in the early hours of Valentine's Day last year when he fatally shot Reeva Steenkamp.
Judge Masipa said: "Having regard to the totality of this evidence in this matter, the unanimous decision of this court is the following: on count one, murder ... the accused found not guilty and is discharged.
"Instead he is found guilty of culpable homicide."
Sky News reporter Alex Crawford was inside and said: "I'm sure that didn't come as any great surprise for the Pistorius family but they were extremely muted.
"There was definitely no sense of celebration or anything else from the Pistorius's.
"I think this was not the verdict that either family wanted."
It's not the first time the athlete has shown his faith in public.
Earlier this year he tweeted a Bible verse from the book of Psalms.
On August 11 he tweeted:
Lord, I know you have a plan for each & everyone that is struggling, please give them peace and help them to believe.
The sentence for a culpable homicide conviction is at the judge's discretion, although it can range from a suspended sentence and a fine to up to 15 years in prison.
Pistorius has had his bail extended and will reappear in court to be sentenced on October 13.