With H1-B visa valid, is there any maximum time limit for travelling outside USA ?

There is no maximum time limit for traveling outside the US when holding H-1B status, but you should be able to convince Customs and Border inspection that you still have a bona fide H-1B job in the US. A job letter confirming your continuing employment may help. I note that we have had H-1B clients who traveled outside the US for longer periods than you are contemplating and returned without incident. Due to the limitations of the Lawyers.com Forums, Alan Lee & Arthur Lee, Esqs.’ (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.