Former WWE woman's wrestler "Chyna" passes out at porn convention...

Former wrestling superster Chyna collapsed at a porn convention in Miami today and was taken to a nearby hospital ... TMZ has learned ... her third such episode in as many days.

Chyna was appearing at the 2012 Exxxotica Expo to help promote Vivid Entertainment's porn parody of "Avengers" -- she plays She-Hulk (yes, really). A rep for Vivid tells TMZ the company was worried about her after yesterday's medical scare ... but Chyna insisted she was ok.

We're told Chyna made it to the convention center today, but passed out in the lobby and was taken to Mt. Sinai Medical Center in Miami Beach.

As TMZ first reported, in addition to passing out yesterday at the convention ... she was kicked out of a party on Thursday night for her unruly behavior, which included passing out in a pool. 

R.M.R.P. The REALvolution...