This will support a plan to provide school places for a million refugees.
The funding has come from the European Union and donors in the Gulf.
Unless refugee families have access to education for their children, Mr Brown said "the death voyages to Europe will not fall but soar".
Refugees are typically away from their own homes for over a decade, Mr Brown said.
It can mean young people missing out on education, training and future job opportunities.
The lack of any access to school and the dangers to children in camps have helped to drive refugees towards Europe, said Mr Brown.
"Unless we can provide chances for children, every day new families will decide the only hope for their children's future is to leave for Europe," he added.
The rate of child marriage among Syrian refugee girls has doubled and many children are forced to work in the black economy, he said.
"To end the exodus and exploitation it is now urgent we agree a plan that will this year guarantee one million Syrian refugee boys and girls not just food and shelter but the chance of schooling."
There are 1.3 million refugee children in neighbouring countries such as Lebanon, Egypt, Iraq, Turkey and Jordan - and many more displaced within Syria.
Mr Brown called for another $750m (Â£528m) to provide education for a million children.
At present, the UN says about 500,000 refugee children have access to schools, including a project in which schools in Lebanon are using a "double shift" system to increase capacity.
Local Lebanese children are using classrooms in the morning and refugee children later in the day.
But it means that a majority of refugee children remain out of school and without international intervention and many young people "may reach adulthood without ever enjoying their first day at school", said Mr Brown
An extra $250m (Â£174m) emergency funding will be provided for educating Syrian refugee children this year, the UN global education envoy Gordon Brown has announced in New York.