导师证明信是办理留学回国证明的材料之一，需要由导师签字，CSC资助人员网上提交即可，非CSC资助人员需要将原件邮寄过去，证明信需要学校专用信纸，类似邀请函信纸。证明信内容如下，仅做参考

To whom it may concern，

The purpose of this letter is to certify that ***** has been in my department as a Visiting Scholar starting from Oct.17，2016 to Oct. 17， 2017 in the Department of ***** at the University of Minnesota. During this period， ***** has been working on field of ******. he has been a valuable member of my research group and her English proficiency has been improved substantially during his stay. I expect that he will continue to have a productive career.

Please let me know if you have any questions.

Sincerely yours，

Professor

Department of *****， University of Minnesota

以上内容由  冯静  老师提供，在此表示感谢！