This disclosure provides a method and system for protecting phone numbers from being exposed to third parties. The method comprises receiving a request, from a caller smart phone, for establishing telephone communication with a callee smart phone, wherein the request contains a code to designate the smart phone of the callee. The method further comprises checking whether the code is formally provided to the callee. The method further comprises: in response to determining that the code is formally provided to the caller, retrieving the phone number of the caller and the phone number of the callee based on the request and establishing a phone call connection via a cellular network with the phone number of the caller and the phone number of the callee.