Based on the wavelength synchronous ultra-dense wavelength division multiplexing passive optical network (UDWDM-PON),a wavelength tracking control method based on signal detected by photoelectric detector (PD) for multi-wavelength optical injection locking is proposed.Specifically,the distribution model of the slave laser (SLD) parameter is established by filtering and detecting the output signal from PD,which is used for the linear scanning control. After the confirmatory experiment with LabVIEW control and data acquisition (DAQ),the control module is reformed by microcontroller unit (MCU) and driving circuit to improve the control precision and encapsulation,so that it can be well applied in multi-channel injection locking.Two-channel injection locking test with two distribute-feedback laser is compared,which using the actively mode-locked laser (MLL) as a multi-wavelength source. It turned out that the slave laser controlled by wavelength tracking module showed better stability under the same injection conditions.