The student said someone slipped her the handwritten note while she wasn't looking. It read, "Go back 2 Africa slave."
The student's mother, Stephanie Lyons, said she was speaking publically about the incident on behalf of her daughter because she worries about her safety. Lyons said her daughter has also been called the "N" word in the past.
"I hurt for my daughter, because I feel like we should be past this and there's no justification for them to just be mean and be like this," Lyons told KGTV, the ABC affiliate in San Diego.
The student is a freshman on the track team and has also made the dean's list. Lyons wants her daughter to transfer to another school in light of the racist incident, the second one in recent weeks.
In the other incident, an Asian-American fraternity at the school posted a video on YouTube where one member appears in "blackface," black makeup simulating African-American skin. It was not connected to the note.
The fraternity, Lambda Theta Delta, has apologized and suspended itself from all campus activities for a year.
"It's an indication that we have some work to do in helping our students and entire campus community understand and value the differences," said Cathy Lawhon, a UC Irvine spokeswoman.
UC Irvine would not comment on whether racism specifically between African-American and Asian-American students is a problem on campus.
Both incidents were under investigation.