Geoffrey Clarke, who is hoping to win a seat on Kent County Council, wrote on his website that babies with such disabilities would be a 'burden' if born.
His views sparked outrage, with one charity calling his views 'abhorrent'.
In comments on his website which have since been removed, Mr Clark called for a Government review to 're-examine the pregnancy abortion time limit. Consider compulsory abortion when the foetus is detected as having Downs, spina bifida or similar syndrome which, if it is born, will render the child a burden on the state as well as on the family'.
His 'manifesto' also said a review should look into medical treatment for people over the age of 80, which the 66-year-old says is 'extraordinarily costly' to the NHS. And he said same-sex marriage was an 'abhorrence'.
Mark Goldring, chief executive of the disability charity Mencap, said: "Mencap is disgusted and horrified by the manifesto of Kent County Council Ukip candidate Geoffrey Clarke who has proposed the compulsory abortion of any foetus with Down's syndrome or spina bifida.
Much has been written about the Paralympics this summer changing attitudes towards disabled people for the better. Yet in the very same year, a council candidate has proposed forced eugenics against disabled people.
"It is abhorrent that Geoffrey Clarke sees disabled people solely as a burden when people with a learning disability lead full lives and make valuable contributions to their communities and families.
"We question if he is fit for public office."
A UKIP spokesman said: "UKIP reject the abhorrent views expressed in the personal manifesto of Mr Geoffrey Clarke.
"The party was not aware of these views when it allowed him to stand under our name.
"We can confirm that Mr Clark has been formally suspended as a UKIP candidate. His membership is undergoing disciplinary hearing.
"UKIP would like to apologise to anyone who has suffered distress as a result of this matter."
The row came as polls show support for Ukip at a record high of between seven per cent and 14 per cent of the vote.