Graeme Whiting, head of the independent Acorn School in Gloucester, told parents to steer clear of JK Rowling's "frightening" books and said they should read classics like Wordsworth, Keats, Shelley and Shakespeare.
Whiting also said other fantasy titles such as 'Lord of the Rings', 'The Hunger Games' and Terry Pratchett's books encourage "difficult behaviour".
"I want children to read literature that is conducive to their age and leave those mystical and frightening texts for when they can discern reality, and when they have first learned to love beauty," he wrote to parents in a blog post.
"'Harry Potter', 'Lord of the Rings', 'Game of Thrones', 'The Hunger Games' and 'Terry Pratchett', to mention only a few of the modern world's 'must-haves', contain deeply insensitive and addictive material which I am certain encourages difficult behaviour in children," Whiting continued.
"These films can damage the sensitive subconscious brains of young children, many of whom may be added to the current statistics of mentally ill young children.
"For young adults, this literature, when it can be understood for what it is, is the choice of many.
"Buying sensational books is like feeding your child with spoons of added sugar, heaps of it, and when the child becomes addicted it will seek more and more, which if related to books, fills the bank vaults of those who write un-sensitive [sic] books for young children."
He added: "Children are innocent and pure at the same time, and don't need to be mistreated by cramming their imagination that lies deep within them, with inappropriate things."
Whiting ended by telling parents: "It is the duty of parents to spend time to study such matters and form their own conclusions, not to think that because the world is filled with such sensational literature they have to have it for their children, because everyone else does.
"Beware of the devil in the text. Choose beauty for your young children."
Mr Whiting refused to comment on his written blog but Nikki Ellis, parent and former teacher at the school, agreed.
"I absolutely agree with Graeme Whiting's views," she said.
"For me, having read the first book of 'Harry Potter' and watched one of the movies I feel that the darkness of the books is so palpable that it wasn't the sort of thing that we would want to expose young children to in their formative years.
"I thinks there's an element that's so detailed and about occultism that it can desensitise children to the dark things in the world at a time when we want to build them up in a positive way.
"They are being exposed to things that can drag them into the dark world and the occult.
"And particularly in 'Harry Potter' it suggests that ordinary people are boring or wrong and only the people who have magic powers are interesting. And right from the beginning the child is orphaned. These things are portrayed in a graphic way."
She suggested that children should not read 'Harry Potter' books before the age of 12 and warned parents off children's favourite Roald Dahl.
"I love the humour of Roald Dahl but there's a degrading element to his books. There are better books out there for children," she added.
Acorn School has been assessed as "outstanding" by Ofsted and its ethos is to "educate students as threefold human beings, nurturing the will, feeling, and thinking elements which are related to the head, heart, and hands".