Alan Evans, 51, asked to access to his 11-year-old daughter Jasmine's file after he became concerned with how she was being treated at Tregolls School in Truro, Cornwall.
Evans found five distressing photos of his daughter taken in 2013, when she was only nine-years-old.
He said: "I saw the photographs and found them incredibly upsetting. She is behind a childproof gate, crying and on the floor in her underpants."
Evans instantly removed Jasmine from the school and now home-schools her as he says the experience has left her "too scared to re-join a classroom environment".
A spokesperson for the school said the photos were taken shortly after it had re-opened after being placed in special measures. They added that the school now has a new headteacher and board of governors.
Jasmine was excluded for hurting a member of staff before Christmas in 2012, but Evans felt the school was failing in their duty of care which was why he asked to gain access to the files.
Evans said: "I think they should have been helping her instead of photographing her and as a result they've failed in their duty of care.
"To me the photographs are gross misconduct and I took her out of the school there and then.
"She'll never go back to school and suffers badly from anxiety and separation disorders."
Evans, a nurse who is married to Janet Evans, 42, has accessed local authorities of turning a blind eye to the photos.
He said: "Nobody will investigate this and I want to know why. I have approached the educational authorities and social services, neither of whom want to know."
Alan said the burden of tutoring his daughter at their home in Lanner, Cornwall, was "huge" and the family was suffering financially as a result.
He said: "It's had a massive effect on our lives and as Jasmine is non-verbal, she struggles to express herself.
"She has no friends and no social life outlet so we have to constantly try to keep her amused.
"It's costing us an arm and a leg and we are really hitting a brick wall but despite this she's actually doing better educationally since she was taken out of school."
Matt Middlemore, headteacher at Tregolls School - An Academy said in a statement: "This relates to a period of time when Jasmine was under the care of a different staff, head teacher and governing body than we have today.
"As far as we are aware the school acted to the best of its ability at the time.
"Jasmine left the school within the first four months of Tregolls Academy opening, when it was recommended that her needs would be best met by a specialist provision.
"Tregolls School was put into special measures in 2011 and reopened in 2012 as an academy.
"We take the dignity and safety of all pupils very seriously as evidenced by our recent outstanding grade by Ofsted for safeguarding."
Cornwall Council said it could not comment on individual cases.
A spokesman said: "The council's children's services authority works closely with schools and with parents and carers to provide the highest possible quality of provision to meet the needs of all children in Cornwall.
"It supports schools to follow due process in all circumstances relating to children with special educational needs."
A spokesperson from the National Autistic Society said: “Although we can't comment on the specifics of this case, it’s important to point out that all parties seem to agree that the school was not the right place to meet Jasmine's needs.
"Unfortunately, far too many children with autism, like Jasmine, don't get the education they need. According to NAS statistics 30% of parents feel that their child’s educational placement is not adequate and 43% of young people with autism feel teachers don't know enough about the lifelong condition.
"Autism is a spectrum condition so, while all children and young people with the lifelong disability share certain difficulties around social communication and interaction, it affects them in different ways.
"Every child with autism is different, so a 'one size fits all' approach simply doesn’t work.
“Autism can have a profound effect on children and young people, as well as their families, but the right support at school can make a huge difference and help them to reach their full potential.”
Warning: some may find the photos in the gallery below upsetting.