去美国留学经济担保证明不是自己的直系亲属可以吗?

No, financial support does not have to be from direct relatives. In fact, any financial support, from business, institutions, from government, from strangers, from scholarship, are perfectly acceptable. However, this financial support must be legitimate. You will be asked for bank and any financial documents showing actual money available to support you.

必须是直系亲属