A synchronization method performed by a synchronization apparatus, comprising: determining reference user equipment, UE, wherein the reference UE can communicate with a reference base station and a to-be-synchronized base station at the same time, and the reference base station and the to-be-synchronized base station have completed frequency synchronization relative to a same clock reference source; receiving a moment T1 that is sent by the reference base station and at which the reference base station receives the synchronization reference signal, wherein the moment T1 is a moment that is determined based on a current frame number and frame timing of the reference base station and at which the reference base station receives a synchronization reference signal sent by the reference UE; and receiving a moment T2 that is sent by the to-be-synchronized base station and at which the to-be-synchronized base station receives the synchronization reference signal, wherein the moment T2 is a moment that is determined based on a current frame number and frame timing of the to-be-synchronized base station and at which the to-be-synchronized base station receives the synchronization reference signal sent by the reference UE; determining timing offset between the to-be-synchronized base station and the reference base station according to the moment T1 and the moment T2; performing calibration on the to-be-synchronized base station according to the timing offset, so as to complete frame number and frame timing synchronization relative to the reference base station by adjusting the frame number and frame timing of the to-be-synchronized base station according to the timing offset; and after the performing calibration on the to-be-synchronized base station according to the timing offset, further comprising: periodically determining the timing offset between the reference base station and the to-be-synchronized base station; and when the timing offset is greater than a first threshold and less than a second threshold, enabling the reference base station and the to-be-synchronized base station to perform the frequency synchronization relative to the same clock reference source; or when the timing offset is greater than a second threshold, performing the calibration on the to-be-synchronized base station according to the timing offset. determining reference user equipment, UE, wherein the reference UE can communicate with a reference base station and a to-be-synchronized base station at the same time, and the reference base station and the to-be-synchronized base station have completed frequency synchronization relative to a same clock reference source; receiving a moment T1 that is sent by the reference base station and at which the reference base station receives the synchronization reference signal, wherein the moment T1 is a moment that is determined based on a current frame number and frame timing of the reference base station and at which the reference base station receives a synchronization reference signal sent by the reference UE; and receiving a moment T2 that is sent by the to-be-synchronized base station and at which the to-be-synchronized base station receives the synchronization reference signal, wherein the moment T2 is a moment that is determined based on a current frame number and frame timing of the to-be-synchronized base station and at which the to-be-synchronized base station receives the synchronization reference signal sent by the reference UE; determining timing offset between the to-be-synchronized base station and the reference base station according to the moment T1 and the moment T2; performing calibration on the to-be-synchronized base station according to the timing offset, so as to complete frame number and frame timing synchronization relative to the reference base station by adjusting the frame number and frame timing of the to-be-synchronized base station according to the timing offset; and after the performing calibration on the to-be-synchronized base station according to the timing offset, further comprising: periodically determining the timing offset between the reference base station and the to-be-synchronized base station; and when the timing offset is greater than a first threshold and less than a second threshold, enabling the reference base station and the to-be-synchronized base station to perform the frequency synchronization relative to the same clock reference source; or when the timing offset is greater than a second threshold, performing the calibration on the to-be-synchronized base station according to the timing offset. periodically determining the timing offset between the reference base station and the to-be-synchronized base station; and when the timing offset is greater than a first threshold and less than a second threshold, enabling the reference base station and the to-be-synchronized base station to perform the frequency synchronization relative to the same clock reference source; or when the timing offset is greater than a second threshold, performing the calibration on the to-be-synchronized base station according to the timing offset.