The present application provides an antenna assembly and an electronic device. The antenna assembly comprises a first radio frequency signal source, a first antenna radiator, a second antenna radiator, a first adjustment circuit, a second adjustment circuit, a mode switch and a controller, wherein the controller generates first, second and third control signals, the first radio frequency signal source generates a first radio frequency signal, the first adjustment circuit adjusts an equivalent electrical length of the first antenna radiator under the control of the first control signal to generate first electromagnetic wave signals of different bands, the second antenna radiator comprises a first portion arranged at a preset clearance away from the first antenna radiator, the first portioncouples the first electromagnetic wave signals to generate second electromagnetic wave signals, and when the mode switch is in a first state under the control of the second control signal, the secondadjustment circuit is electrically connected with the first portion, and the second adjustment circuit adjusts the equivalent electrical length of the first portion under the control of the third control signal to radiate the second electromagnetic wave signals.