The name of the dead student has not been released, the Orlando Sentinel reported.
Campus police, responding to a fire alarm call in Tower 1 residence hall, received a 911 call about shots being fired and found a man who died of an apparent self-inflicted gunshot wound, the university said. As investigators examined the scene, they found a handgun, an assault weapon and bombs.
The Orlando campus reopened for classes and regular operations at noon Monday after all of the improvised explosive devices were removed from Tower 1, the university said on its website.
The residence hall, home to about 500 students, was a crime scene and would remain evacuated until the FBI has "cleared" the building, university spokesman Grant Heston said.
Authorities said they were interviewing witnesses.
UCF Police, the FBI and Orange County Sheriff's Office bomb squad have been on campus since early Monday morning, the Sentinel said.
The explosives found in a bag near the student "have been made safe" by law enforcement officers and school officials said they were removed, the Sentinel said.
Heston said officials were investigating how and why the student had the cache of weapons in his room. Firearms are not allowed on campus, a university official said.
The spokesman said authorities hadn't found an explanation or manifesto. He said the man's body, the weapons and the explosive devices were found in one of the rooms in the man's dorm apartment.
Law enforcement officers found a handgun, an assault weapon and bombs, a campus spokeswoman said.
Erin Sayre, a student who was evacuated from the residence hall, told the Sentinel the lack of information students received about the situation was frustrating and that she now felt unsure about how safe she was on campus.
"These walls are paper-thin," Sayre said of the Tower 1 dorm. "You can hear the toilet flushing upstairs. If it was a bomb, how many floors could it have taken out?"