The group of 25 squatters, called Osney Open House, took over part of Osney Power Station on 26 February.
Oxford County Court granted Said Business School an interim possession order on Wednesday.
The group previously claimed squatters rights in an unused car showroom owned by Wadham College.
A university spokesman said the power station - from where a man had to be taken to hospital after being exposed to toxic sub-tropical seeds - was not safe for occupation.
Part of the station is used as a store for Oxford University's museums, but Osney Open House is not occupying this area.
Activist Miranda Shaw said: "The university owns so much of the city centre.
It would be incredible if the university could show leadership in the face of corrosive cuts at both a national and city level.
"We are facing a social emergency and this is now the second time that oxford university has closed its doors."
The spokesman said the group had "made a serious point" by drawing attention to "the plight of these people who need somewhere safe to live".
Previously Osney Open House had been using a car showroom in Iffley as a squat for nearly two months.
Owners Wadham College gave the squatters a stay of execution until 27 February, when work to demolish the showroom began.
The site will be turned into student accommodation.
Oxford University said it had given the squatters until Sunday to leave "to pack up their belongings".
Squatters who have taken over a second building owned by Oxford University have been given until Sunday to leave.