The invention provides a laser dense wavelength division multiplexing stable wavelength control method. The method comprises the following steps of obtaining a corresponding relation between a set voltage value and an output voltage value, a corresponding relation between the set voltage value and a set corresponding temperature, and a corresponding relation between the set voltage value and a monitored temperature; obtaining a monitored temperature threshold range, and a target set temperature value, the upper limit hysteresis temperature and the lower limit hysteresis temperature of a refrigerator controller; obtaining a target set voltage value and a target output voltage value, and outputting the target output voltage value to the refrigerator; and detecting the real-time temperature of the laser during working in real time, wherein when the real-time temperature is within the hysteresis temperature ranges, the laser is started. According to the method, the working wavelength of the laser is offset within +/-0.02 nm, and the problem of light crosstalk between the DWDM channels is effectively solved.