By TMZ Sports

UFC world champion Ronda Rousey is continuing her feud with WBC/WBA welterweight and junior middleweight champion Floyd Mayweather Jr. -- reacting back to his recent comment about her earning ability.

Of course, the two have been trading verbal shots for months in the press -- and when Ronda was out walking her dog in L.A. yesterday ... she blasted him again, claiming she's the REAL top earner in combat sports.

After this year's ESPY Awards, where Rousey beat Mayweather for the top fighter award, she took a dig at his past domestic abuse troubles by asking what it felt like to be 'beaten by a woman' on live television.

Mayweather responded during an ESPN interview weeks later, by stating when Rousey earns "$300 million" in a single fight then she can call him - a knock on the many reports that UFC fighters are underpaid.

So Rousey responded in kind when TMZ Sports caught up to her, taking a crack at Mayweather's ability to read and write. During the height of Mayweather's feud with rapper Curtis '50 Cent' Jackson, the rapper claimed Mayweather had an ongoing struggle with his ability to read. 

"He said 'You make $300 million a night, then you can give me a call', and I actually did the math and given the numbers of my last fight, I'm actually the highest paid UFC fighter and I'm a woman. I think I actually make 2-3 times more than he does per second. So when he learns to read and write, he can text me."

She continued, "I think I actually make 2-3 times more than he does per second ... so when he learns to read and write, he can text me."

The photog asked, "So you actually make more than he does?"

Ronda responded, "Yeah, I'm just more efficient."