Floyd Mayweather Jr.'s baby mama claims the boxer struck her "multiple times in the head with his fist" and then threatened to kill her ... this according to documents obtained by TMZ.
Josie Harris went to court yesterday and filed a request for a restraining order against Mayweather -- and in the docs she states that Floyd came into her Las Vegas home Thursday morning and awoke her by, "pulling me by my hair and throwing me on the ground in my living room and began punching me in my head."
She claims Floyd then began "dragging me on the floor and twisting my arm back ... in attempt to try and break it."
According to the documents, Josie claims Floyd "continued to beat me in front of [the couple's three children]."
Josie claims that Floyd threatened the children -- saying if they "ran or tried to call the police he would beat them the same way."
In the docs, Josie also says Mayweather "yelled and screamed that he was going to kill me and my boyfriend and make sure we are taken care of."
Interestingly -- Josie claims, in the docs, Mayweather had been at the house roughly two hours before the alleged attack -- and was yelling at her about her new boyfriend.
Josie claims she had to call police ... who arrived and escorted Floyd out of the home.
But according to Josie, the boxer didn't stay away ... and Mayweather re-entered the home through her son's side bedroom door -- and that's when the alleged attack went down.