I submitted my article to a journal on 12.01.2016. I asked many times about status of my paper. I have not received a reply from the editor even though my article has been evaluated since 17 months. what do you think about unethical situation?
If they're not answering emails, that is a very worrying sign. I would suggest sending an email to the editor (cc'ing the editor-in-chief and any other relevant people at the journal) saying that you are very concerned that they are not answering your emails, and that if they don't answer this email, you intend to withdraw the paper.
Then, if they don't answer the email within a reasonable time, send them another email withdrawing the paper.
While the course of action suggested by Peter is certainly correct and appropriate after a long wait, I don't think it's appropriate in your situation.
You said you have asked the editor many times and never heard back for 17 months (even if they have difficulty finding reviewers, they can at least let you know). That's utterly unaccaptable and never occurs with any good journal. Therefore, I suggest to without further delay withdraw your paper and re-submit to a good journal instead.