The invention discloses a smart phone-based sensor data backup system and method. The system comprises a wireless sensor, a smart phone and a remote server. The wireless sensor is a microcontroller with a wireless communication module. The wireless communication module has a wireless local area network communication function. The wireless sensor is provided with a gateway program. The smart phoneis provided with a human-machine interaction interface and a wireless local area network communication module. A client application is arranged on the smart phone. The remote server is provided with anetwork interface and is connected with a wide area network or a local area network. A server application is arranged on the remote server. According to the invention, automatic backup of collected data from the wireless sensor to the remote server is realized through the smart phone; manual intervention of a user is not needed; and the risk of failures such as repeated backup, backup loss and the like caused by manual operation is reduced.