I have recently graduated, applied for OPT and received my EAD card last week, I found that the validation period is two years(FROM:07/17/2017 TO:07/16/2019). is it okay to keep like this or should I report to USCIS ? please Guide Me.

USCIS might know it, when they have issued you the card in the first place. Just check with your university, to see if your SEVIS also carries the same authorization for 2 years. If it does, then you have no issues.

I agree with Ramanan. Check with University on authorization dates for SEVIS. Do not take your EAD card or university might file unnecessary documents that will confuse and harm you. If USCIS has issued a document, they know what they are doing.