The 20-year-old Prince spent eight weeks working in an orphanage in an African country called Lesotho where Aids is a huge problem.
While he was there he made a film for TV and in interviews for it spoke about his mum, the Princess of Wales.
He said that he wanted to make his mother proud but added that no-one could take over her role.
In the film, Harry said: "I always wanted to go to an Aids country to carry on my mother's legacy as much as I can.
He thinks his mum would have supported his work with Aids orphans.
"I believe I've got a lot of my mother in me, basically, and I think she'd want us to do this, me and my brother," he said.
Hear story
Country profile: Lesotho
Try the Prince Harry quiz
