<p id="p-0001" num="0000">The present invention discloses a device and method for controlling a lasing wavelength of a tunable laser, and a wavelength division multiplexed-passive optical network having the same.</p><p id="p-0002" num="0000">In a device and method for controlling a lasing wavelength of a tunable laser, and a wavelength division multiplexed-passive optical network having the same, it is possible to improve performance of the wavelength division multiplexed-passive optical network by automatically controlling a lasing wavelength of a tunable laser to be matched with a transmission wavelength of a wavelength division multiplexer/de-multiplexer using optical power or optical beating components obtained by a reflected optical component which is Raleigh backscattered or reflected, and is generated on an optical fiber.</p>