A key negotiation method and an electronic device are provided, and relate to the field of communications technologies. Specifically, the method includes: An IoT control device multicasts, in a first local area network, a discovery message that carries a first public key, and sends a second ciphertext to a first IoT device after receiving a first ciphertext and a second public key. After receiving a third ciphertext from the first IoT device, the IoT control device decrypts the third ciphertext based on a first session key, to obtain a second signature and second session information; verifies the second signature based on a long-term public key of the first IoT device; and performs encrypted communication with the first IoT device based on the first session key after the second signature is successfully verified.