Number writing method and system

The invention discloses a number writing method and system, relates to the technical field of Internet of Things, and mainly aims to prevent an Internet of Things device from being written with a wrong authorization serial number. According to the main technical scheme, the method comprises the following steps: when a number writing terminal determines that the Internet of Things equipment needs to write a number, acquiring equipment information of the Internet of Things equipment; the number writing terminal sending a serial number issuing request carrying the equipment information to an authorization server; the authorization server generating an authorization serial number based on the equipment information under the serial number issuing request and issuing the authorization serial number to the number writing terminal, and the authorization serial number being a basis for acquiring an OTA upgrade package when the Internet of Things equipment performs OTA upgrade; and the number writing terminal writing t