A wavelength calibration method for a microring filter, wherein the microring filter comprises a plurality of microrings, and the method comprises: selecting (201, 301, 401, 501) N wavelengths from M wavelengths, and performing the following operations on the microring filter for each of the N wavelengths, to obtain N sets of calibrated voltages, wherein N is less than M: A1: adjusting (202, 302, 402, 502) thermal tuning power of the plurality of microrings by using one set of voltages defined by first step units within a first voltage adjustment range, and obtaining a plurality of sets of voltages that enable monitored optical power to have an extreme value; and A2: using (203, 303, 403, 503) one of the plurality of sets of voltages as a reference according to a sequence of sorting the plurality of sets of voltages in ascending order of voltage values, adjusting the thermal tuning power of the plurality of microrings by using another set of voltages, defined by second step units within a second voltage adjustment range repeatedly and sequentially scanning the plurality of microrings, and determining one of the sets of calibrated voltages from the plurality of sets of voltages, wherein the set of calibrated voltages enables a change of a value of the monitored optical power obtained by adjusting a same microring during the repeated sequential scans to remain within a predefined range, and the monitored optical power is to be not less than a preset value when the monitored optical power has an extreme value which is a maximum value, and the monitored optical power is to be not greater than another preset value when the monitored optical power has an extreme value which is a minimum value; and obtaining (204, 304, 404, 504), through calculation based on the N sets of calibrated voltages, M - N sets of calibrated voltages corresponding to M - N wavelengths of the M wavelengths. A1: adjusting (202, 302, 402, 502) thermal tuning power of the plurality of microrings by using one set of voltages defined by first step units within a first voltage adjustment range, and obtaining a plurality of sets of voltages that enable monitored optical power to have an extreme value; and A2: using (203, 303, 403, 503) one of the plurality of sets of voltages as a reference according to a sequence of sorting the plurality of sets of voltages in ascending order of voltage values, adjusting the thermal tuning power of the plurality of microrings by using another set of voltages, defined by second step units within a second voltage adjustment range repeatedly and sequentially scanning the plurality of microrings, and determining one of the sets of calibrated voltages from the plurality of sets of voltages, wherein the set of calibrated voltages enables a change of a value of the monitored optical power obtained by adjusting a same microring during the repeated sequential scans to remain within a predefined range, and the monitored optical power is to be not less than a preset value when the monitored optical power has an extreme value which is a maximum value, and the monitored optical power is to be not greater than another preset value when the monitored optical power has an extreme value which is a minimum value; and obtaining (204, 304, 404, 504), through calculation based on the N sets of calibrated voltages, M - N sets of calibrated voltages corresponding to M - N wavelengths of the M wavelengths.