Is there a way through which I can disable a validation rule in Salesforce1 (User logging in from iPhone) but it should be activated while user logs in from laptop.
Validation rules verify that the data a user enters in a record meets the standards you specify before the user can save the record.
Validation rules apply to new and updated records for an object, even if the fields referenced in the validation rule are not included in a page layout or an API call.
Now, you could try to write a validation rule to check for Salesforce1 and skip it, but unfortunately that isn't possible. It isn't that easy to detect if you are in Salesforce1 under any circumstances, especially not in a validation rule.