The embodiment of the invention provides a processing method and device for a PDU session. The processing method comprises the steps that an access device receives a PDU session establishing request message sent by a core network control surface function entity, wherein the PDU session establishing request message at least carries configuration information of a default PDU flow, and the default PDU flow is used for transmitting data packets which cannot be matched to any dedicated PDU flow; and the access device conducts corresponding processing according to the PDU session establishing request message. By carrying the configuration information of the default PDU flows in the PDU session establishing request message, the process that the access network establishes context of the session and the PDU flows on the basis of the PDU session can be effectively solved.