Speaking during PMQs in the Commons, he said: "This week the Prime Minister finally did the right thing. When Donald Trump told women they should go home, she called it out as unacceptable.
"Let me be clear, Donald Trump's actions are textbook racism, they are repugnant and diplomatic politeness should never stop us from saying so.
"Will the Prime Minister now on reflection also take the opportunity to call out and condemn the racism of the go home van, that she created in coalition government with the Liberal Democrats."
Mrs May replied: "I said at the time that, that was too blunt an instrument - but there is an important issue here, which is that the public expect us to have a fair immigration system which deals with those who are here illegally and that is what we need to do."
She added: "I have strongly condemned those comments made by President Trump."
Mr Blackford claimed the "Tory Party shares more with the extremes of Donald Trump and Nigel Farage".
He said: "When the Prime Minister implemented the hostile environment policy her party stayed silent. When she delivered the racist go home vans the Tories remained silent. When asylum seekers are deported to places where their lives are at risk the Tories stay silent, and yes Mr Speaker when faced with the racist columns written by the former foreign secretary, they stay silent.
"Isn't the member for Aberconwy (Guto Bebb) correct Prime Minister when he warns that the Tories are appealing to the type of nationalism that has seen Ukip grow.
"While the Tory Party shares more with the extremes of Donald Trump and Nigel Farage, isn't it any wonder Mr Speaker that Scotland looks on in horror?"
Mrs May replied: "The Conservative Party is a party for the whole of the UK and the only party in this House which is appealing to blatant nationalism is the party that wants to take Scotland out of the UK."