Provided are a wavelength lock, and a wavelength locking method and apparatus, which are used for solving the current problems that a correct frequency offset cannot be detected and high precision within a full-wave band range cannot be achieved when a wavelength shift is relatively large. A detection processing circuit in the wavelength lock is used for adjusting, according to an optical signal reflected and transmitted by the first F-P etalon and an optical signal reflected and transmitted by the second F-P etalon, a pin current of the laser, so that a frequency offset of the laser is withinan error range. A frequency range of a transmission function of the first F-P etalon in a linear region within a period is not greater than the required minimum detection precision. The period lengthof a transmission function of the second F-P etalon is not less than twice the maximum value of the frequency offset of the laser. The frequency of an optical signal with the pre-set wavelength is located in linear regions of the transmission function of the first F-P etalon and the transmission function of the second F-P etalon.