The commission proposed on Wednesday a 9 billion euro loan to Ukraine to keep the country going as it struggles to fend off the Russian invasion and wants to set up a reconstruction facility for after the war.
"Our lawyers are working intensively on finding possible ways of using frozen assets of the oligarchs for the rebuilding of Ukraine. I think Russia should also make its contribution," she told ZDF television.
Von der Leyen also said she favoured coupling the long-term reconstruction of Ukraine with reforms needed for it to join the European Union.
While Ukrainians see their future within the EU, certain standards have to be met for membership in areas such as the rule of law and in the economic and political spheres, she said.
"The accession process depends a lot on how the candidate behaves and what it does. Ukraine wants to join the EU at any price which means the motivation is great to undertake the reforms that are needed," she said.
"We will have to co-finance the reconstruction of Ukraine ... it makes sense to tackle reforms at the same time, for example against corruption or building up the rule of law," she said.