"I don't like attacking politicians' kids -- I've been on the receiving end of this," he said.
"I would never do it to the Obama kids, I've never done it to the Bush kids, I wouldn't do it to Chelsea [Clinton]," he added. "The problem is this is rampant corruption."
Reacting to clips from the younger Biden's Tuesday interview with ABC News, Trump said it was interesting to hear Biden mention his experience on the Amtrak's board when reacting to questions about his foreign business dealings.
"Isn't the next obvious question, 'What qualified you to sit on the board of Amtrak?'" Trump asked.
Trump told host Laura Ingraham he believed Biden got his place on the Amtrak board because his father, a former U.S. senator from Delaware, was vice president.
Trump remarked he would ride Amtrak weekly while attending Georgetown to commute on weekends between New York and Union Station in Washington.
"That does not qualify me to sit on the board of Amtrak," he said.
"It is rampant corruption and it ... shouldn't happen and it's disgusting and quite frankly it is disqualifying."
Trump also offered a response to Hunter Biden's remarks about himself and his elder brother, Donald Trump Jr.
In response to Eric Trump joking to a Minneapolis rally crowd that shouts of "Lock her up!" might change to "Lock him up!" -- in an apparent reference to Biden -- the son of the former vice president told ABC News, "Who cares?"
"Barnum and Bailey," he remarked, making a nickname for Donald Trump Jr., and calling him, "not somebody I really care about."
In response to Biden, Eric Trump told Ingraham there is a difference between himself and the younger Biden.
"The difference between us and Hunter is, when my father became commander-in-chief of this country, we got out of all international business. When his father became vice president of the United States, he got into international business."