Disclosed is a method of loading a signature rule and a network device thereof. According to an example of the method, the network device may first receive a signature rule library sent by a cloud server, wherein the signature rule library contains one or more signature rules, each of which is associated with corresponding device type configuration information. The network device may determine for each signature rule whether device type configuration information associated with the signature rule matches local device type configuration information of the network device. If the device type configuration information associated with the signature rule matches the local device type configuration information of the network device, the network device may load the signature rule.