Abstract: A key update method, a network device, a system, and a storage medium, applied to a Bluetooth mesh network. The Bluetooth mesh network includes at least two mesh nodes. A configuration node is a mesh node in the Bluetooth mesh network, and the configuration node is configured to configure a network key of the Bluetooth mesh network. The configuration node determines a first mesh node from mesh nodes in the Bluetooth mesh network, where a network key locally maintained by the first mesh node is inconsistent with a current network key of the Bluetooth mesh network. Therefore, the configuration node encrypts the first network key by using a device key of the first mesh node, to obtain a first ciphertext, and sends a first message that carries the first ciphertext, so that the first mesh node obtains the first network key.