The humanitarian charity says the jihadists have been murdering, injuring and displacing civilians across north-eastern Nigeria, as well as destroying water sources, crops, schools and health centres.
It says four million now need emergency assistance, with almost half of them being forced to leave their homes.
Because of ongoing fighting between Boko Haram and the Nigerian military it has been difficult for charities to bring assistance to suffering civilians. It has also limited the ability of journalists to cover the situation.
Christian Aid has spent almost £1 million so far in north-east Nigeria and has received funding from the Dutch Church aid agency ICCO, the Dutch government and the UK government's START Fund.
Nick Guttmann, head of humanitarian work at Christian Aid, visited north-east Nigeria in October.
He told Premier: "They [civilians] told of horrific stories of being chased out, Boko Haram coming through their village, lining them up, shooting them, burning the villages, burning the crops, destroying the schools, destroying the health centres, destroying the water systems."
He added that the Nigerian military had weakened Boko Haram since he was there: "There's one area which I couldn't go to, Monguno... and that is now accessible, so our teams and our partners will be going to those areas providing food and water and other essential supplies to the people there.
"We need to be thinking of the people who've been suffering so much... praying that they can go home to their loved ones... and that they can restart their lives again in peace and tranquility, which at this time year we all want to see more than anything else."
Listen to Premier's Aaron James speaking to Nick Guttmann: