The invention discloses a household appliance, a communication system and method for the household appliance and a cloud server, and the cloud server. The method comprises the following steps that: the household appliance acquires a first cyphertext encrypted by a cloud server public key in an authorization module, and transmits the first cyphertext to the cloud server; the cloud server receives the first cyphertext, decrypts the first cyphertext through a cloud server private key, encrypts the decrypted first cyphertext through a household appliance public key to obtain a second cyphertext, and transmits the second cyphertext to the household appliance; the household appliance receives the second cyphertext, determines the cloud server as a legal cloud server according to the second cyphertext, encrypts a generated confirmation message through a preset encryption algorithm, and sends the encrypted confirmation message to the cloud server; and the cloud server receives the confirmation message, and establishes a connection with the household appliance when the household appliance is determined as the legal household appliance according to the confirmation message. Through adoption of the household appliance, the communication system and method and the cloud server, the security of communication information between the household appliance and the cloud server is improved, and the identity authentication speed is increased.