Joe Francis -- I'm Innocent ... And I Have Video Evidence!

Joe Francis insists he never laid a hand on the chick who claims the "Girls Gone Wild" honcho assaulted her in his Hollywood mansion -- telling TMZ, he even has security footage to PROVE he's innocent.

Joe tells us, he has THREE surveillance cameras that captured the 3-woman altercation at his home back in January -- from several different angles -- and he wasn't involved.

According to Francis, two of the girls were fighting EACH OTHER -- and all three were escorted out of his house for being unruly.

It's a drastically different story from what the girls told police -- that Francis grabbed one of them by the throat and hair, and slammed her head into the tiled floor of his house ... four times.

Francis was charged with one count of assault causing great bodily injury as a result -- in addition to three counts of false imprisonment and one count of dissuading a witness from filing a police report.

But Francis insists it's all BS -- telling us, there wasn't even a tiled floor anywhere near the scene of the fight. TMZ spoke to two other people at Francis' home that night -- and both are prepared to testify in Joe's defense.