According to the police report obtained by TMZ, 40 Glocc -- real name Lawrence White -- was arrested on October 3rd ... after he allegedly unleashed a brutal beating on the woman.

Cops say 40 Glocc accused his GF of "playing him" -- so he hit her several times about the head, face, legs and rib area ... and choked her to the point where she "could not speak or breathe."

In the report, the GF claims Glocc strangled her twice more before falling asleep -- at which point, she snuck away and called 911.

When cops arrived, officers noticed bruising and swelling all over her face -- and "significant bruising to her throat, consistent with strangulation injuries."

40 Glocc -- reportedly a member of the Crips -- was arrested as he tried to drive away from the house.

The woman then told police Glocc had been abusing her for more than a year ... once handcuffing her and locking her in the truck of his car -- but she was too afraid to go to police, fearing he would kill her.

Glocc was taken to a nearby jail -- where he was charged with three counts of domestic battery by strangulation and coercion with force.