If you registered a domain name from a registrar, can this registrar suspend your domain name even if it is not yet expired?
Unless a company files UDRP against the domain, it gets complaints of abuse, or you used a stolen paypal/credit card to purchase the domain I don't see why the registrar would suspend the domain. Although your question was a bit vague... why do you ask?
Or the OP violates any term of the registrar's contract, or the registrar gets a court order to suspend it. To the OP: you bet the registrar can suspend the domain name. But many will have a good reason for doing so.