A packet security method and apparatus adjusts a security level of the packet according to a feature of the packet. The packet security method includes detecting a feature of a packet to be transmitted, determining a security level of the packet according to the detected feature, and generating a security packet according to the determined security level. The feature of the packet is at least one of a destination address of the packet, a transfer protocol of the packet, a packet size, an application for the packet, and a designated security level for the packet. According to the method, the security function is adoptively applied according to the feature of the packet being transmitted, and thus flexibility can be provided in the application of the security function to achieve an efficient use of resources.