A method and apparatus for wavelength selection of onu/ont in passive optical network

The present invention relates to a method for selecting a wavelength of an optical network terminal in a passive optical network, comprising: a usage wavelength candidate selecting step where a prestored basic wavelength is selected as a usage wavelength candidate or a wavelength is changed and the changed wavelength is selected as a usage wavelength candidate in a case that a predetermined wavelength changing condition is satisfied; a downward synchronizing step where frame synchronization is obtained for a downward signal having the same wavelength as the selected usage wavelength candidate; and a terminal registering step where a registration request message is transmitted to an optical line terminal (OLT) which has transmitted the downward signal in the case that the frame synchronization is obtained, and allocating the usage wavelength candidate as a usage wavelength used in communications with the optical line terminal and registering the usage wavelength in the optical line terminal in a case that a registration admission message is received from the optical line terminal.