The present invention provides a synchronization method of user equipment and user equipment, where the method includes: when the user equipment accesses a millimeter-wave band network, performing first synchronization in a cellular band by using a cellular band network that covers the millimeter-wave band network; and performing second synchronization in a millimeter-wave band by using the millimeter-wave band network. In the present invention, after the first synchronization in the cellular band is performed, the second synchronization in the millimeter-wave band is performed by using the millimeter-wave band network, which avoids a case in which the user equipment acquires a PSS in a PSS synchronization window that slides in the millimeter-wave band for a long time, thereby reducing overheads, narrowing a range of the synchronization window, and accelerating detection of a PSS in the millimeter-wave band, so that the user equipment quickly and accurately performs synchronization in the millimeter-wave band.