was tried for Nicole's murder, as well as friend Ron Goldman, in 1995 but was acquitted.
Both Nicole and Ron's family saw the verdict as a serious miscarriage of justice.
The entries are examined in new documentary OJ and Nicole: An American Tragedy, airing on the 25th anniversary of Simpson's acquittal on the Investigation Discovery channel.
Her sister, Tanya said of the beatings that perhaps Nicole knew her death was "destiny," adding: "Maybe subconsciously she knew something was going to happen
"Maybe that’s why she kept real detailed diary entries."
The shocking diaries were found stashed in a safety deposit box alongside photographs of Nicole's injuries and grovelling apology letters from Simpson.
The documents were dismissed as heresay by a judge during the original trial.
In 2016, a documentary re-visited some of the entries, including one that simply states: “'He hit me while we f***ed”.
The newer doc reveals more harrowing abuse, including one passage that describes how the footballer beat Nicole "for hours" after a friend's anniversary party in 1978.
It reads: "1st time he beat me up after Louis + Nanie Mary anniversary party. Started on the street corner of NYC 5th Ave at about 9.
"Threw me on the floor, hit me, kicked me. we went to the hotel where he continued to beat me for hours and I continued crawling for the door."
Another describes how he smashed her Mercedes with a baseball bat after she came home late - she writes: "I was too afraid to get out of the car".
In one detailing how he ripped her clothes from her after drinks, Nicole says she went to the hospital - but pretended she had been in a bicycle accident.
Another stomach-churning entry recounts how a then-pregnant Nicole pleaded to be let back into their home after he kicked her out, reasoning their daughter was asleep.
Nicole wrote: "OJ was drunk, he never let up. Get out my f house you fat a** liar. I packed a few things together."
The passage continues: "[He said] Let me tell you how serious I am. I have a gun in my hand, get the f*** out of here."
Despite the beatings, Nicole married Simpson in 1985 but she later filed for divorce from Simpson citing "irreconcilable differences".
John Edwards of the Los Angeles Police Department revealed how he attended the couple's home in response to a 911 call.
He said: "“When you have a call come out and the 911 operator puts out on the call that she can hear the woman being beaten in the background, that's serious."
Describing the scene when he arrived, the cop said: "She's wearing nothing but a bra and sweatpants covered in mud and she kept yelling ‘he's going to kill me, he's going to kill me’.
“She was so wet and cold that you could feel her shivering to her bones.
“And I said, ‘well who's going to kill you?’ And she said ‘OJ’.
“She said you guys have been up here eight times before, all you do is talk to him, you never do anything."
On June 13, 1994, 35-year-old Brown's body was found outside her home in Brentwood, Los Angeles.
Restaurant waiter Ron Goldman was also found at her home, in the fetal position in a pool of blood.
The family of Ron Goldman - a 25-year-old restaurant employee who had arrived at Nicole's property that evening to return her mother's glasses - successfully brought a civil case against Simpson in which jury awarded them $33.5 million in damages.
The family have not received a penny and the total now stands at $70 million.
An autopsy found that Brown had been stabbed seven times in the neck and scalp, and had a 5.5in slit across her throat, which had severed both carotid arteries and breached her jugular veins as well as having defensive wounds on her hands.
The wound across her throat was so severe, it almost decapitated her.
But speaking about the upcoming documentary, Investigation Discovery boss Henry Schleiff said: "This documentary is not here to retell the famous trial, but to remember the woman who struggled with domestic violence and now tells her side of the story, in her words, for the first time".