Yujing Zhang, 33, was arrested on March 30 at the president's club carrying two Chinese passports, a computer and four mobile phones, among other devices, the BBC reported.
Zhang, who acted as her own lawyer, maintained her innocence during her closing arguments on Wednesday, telling the court: "I did nothing wrong."
"I went into the Mar-a-Lago to have a visit," Zhang told the jury. "So that's what I want to say, and thank you for your attention."
Zhang faces up to six years in prison when she is sentenced in November.
Despite the guilty verdict the trial did not establish why exactly she was there.
She told agents after her arrest that a friend in China had encouraged her to speak to a member of Trump's family about Chinese-US economic relations.
Trump was staying at Mar-a-Lago that weekend but was elsewhere at the time of the incident.
There has been little comment on Zhang's case in China, reports the BBC.
Hours before Zhang was found guilty, Foreign Ministry spokeswoman Hua Chunying on Wednesday said suggestions of connections between Zhang and the Chinese government were "laughable".
"The US has had too much suspicion lately," Hua told a news conference, "Some Americans could become sci-fi writers now."
( With inputs from IANS )