The disclosure provides a device and a method for antenna impedance matching. The device comprises an application detection module, configured to detect a current state of an antenna of a terminal, and output a matching adjustment signal according to the state; an adaptive control module, configured to perform control over a process of matching adjustment in response to the matching adjustment signal; and a matching adjustable module, configured to, under control of the adaptive control module, perform matching adjustment on impedance of the antenna through an impedance matching network corresponding to the matching adjustment signal. Through the technical solution provided by the disclosure, the problem of single impedance matching mode in the prior art is solved, and further, the effect that differential matching can be performed for various application states of the terminal is achieved.