The Traditional theory of joint crime in criminal law has many dissimilation in telecom network fraud. The cognizance of joint crime of telecom network fraud should have "knowing" subjectively or can be presumed to "know". According to theory of restrictive derivativeness, the knowledge does not require a specific understanding of the extent to which another committed a telecom network fraud, as long as the accomplice has realized that another has committed an illegal act. Unless there is a conspiracy in advance, the joint crime should only exist before the accomplishment of the telecom network fraud.The identification of the offense should confirm the mode of telecom network fraud and whether the property has been obtained or not. Inparallel and division typical modes of fraud crimes, there exist differences in scope of criminal responsibility for aiding the offender, hiding or concealing the property. For the platform operator, a restrictive punishment should be implemented if he commitsany neutral assistance seriously escaping the society.