In a network security processing method and system for selecting one of software and hardware cryptographic modules by means of multimedia session information, the method includes the following steps: subjecting a plurality of packets of a multimedia session to signaling processing so as to obtain multimedia session information contained in the multimedia session, subjecting the multimedia session to a key authentication negotiation and according to the multimedia session information, making a determination to activate one of the software cryptographic module and the hardware cryptographic module. If the hardware cryptographic module is activated, the hardware cryptographic module performs network security processing of the packets of the multimedia session. If the software cryptographic module is activated, the software cryptographic module performs the network security processing of the packets of the multimedia session.