A bandwidth adjustment method includes: determining a bandwidth update value of a channel of a first network system and a bandwidth update value of a channel of a second network system and a bandwidth update value of a protective bandwidth according to a request of a user or a channel condition, so that updated bandwidths of the channels of the first network system and the second network system meet the request of the user or are adapted to requirements of channel conditions. By using the technical schemes, a network resource can be adjusted between multiple network systems when the multiple network systems share one network resource, thereby helping improve the application efficiency of a bandwidth resource and ensuring anti-interference capabilities of the network systems.