Hey 李泽民,
I shall provide you with information about the usage of these words:
1) to donate:
'donate' is a word that is most related to money issues. So, it means the same as ''to give (money, time, etc)'', especially to a charity; ''make a contribution...''
E.g.: ''Shall I donate blood?''
E.g.: ''He frequently donates large sums to charity.
2) to contribute:
''contribute'' is more of a general word, which can be used either to mean that you want to 'give or supply in common with others' or 'help bring about a result (also 'be partly responsible for / be conducive to something'').
E.g.: ''I have been told that he contributes to several charities.''
E.g.: ''I shall not contribute to this conspiracy.''
E.g.: ''All of your reckless actions may have contributed to that tragedy.''
Hope that helps!!!