The party has also pledged to reopen the Dubs programme for unaccompanied asylum-seeking children stranded in Europe.
In February the Government scraped the policy which was meant to benefit as many as 3,000 children but only 350 were allowed into the UK before it was closed.
The British government are also only committed to offering refuge to 20,000 Syrians by 2020.
The Lib Dem leader Tim Farron, who will visit a refugee charity in Cheltenham later, will say: “This is about the sort of country we are.
“The Britain I love is an open, tolerant, united country with a generous spirit and compassion for those in need. I love my country – and I hate it when my government makes me feel ashamed.
“Faced with suffering and trauma on a scale not seen since the Second World War, Theresa May has wilfully chosen to tear up her promises to help some of the most vulnerable children and people in the world.
“In the last two years I have visited refugees in Calais, Lesbos and Macedonia. I’ve looked these refugees in the eye and seen their suffering. By committing to taking 10,000 Syrian refugees a year and reopening Dubs we can do our part to ease that suffering.”
The party has also pledged to increase spending on mental health provisions with a £1bn boost to reduce waiting times and provide extra measures to prevent the number of suicides.
The announcement is part of a wider increase in health spending which the Lib Dems announced last weekend.
Extra spending would be funded by putting 1p on income tax which is expected to raise £6bn annually.
The party has pledged that £1bn of this will be protected for mental health programmes which they describe as being “stretched to breaking point”.
Norman Lamb, the party’s health spokesman, said: “The Liberal Democrats are committed to ending the historic injustice against people with mental ill health.
“Under the Conservative government, services have been stretched to breaking point at a time when the prevalence of mental ill health appears to be rising.”
Mental health has become a significant issue during the election campaign with all major parties committed to reform and extra spending.
Mrs May has announced significant reforms to mental health provision and committed a future government to employing 10,000 additional staff by the end of the decade.