High speed wavelength division multiplexing distributed feedback (DFB) laser is the core device of data communication, and its reliability affects the reliability of the whole communication system. Two burn-in experiments and failure analysis are carried out on the self-developed 25 Gb/s 4-wavelength coarse wavelength division multiplexing(CWDM4) DFB laser, and the working life of the laser is calculated by the three-temperature method. The experimental results show that the burn-in method combining light acceleration(25 ℃, 100 mA) and temperature acceleration(100 ℃, 75 mA) can effectively stimulate the early failure characteristics of weak lasers, the three-temperature method is used to estimate the actual lifetime of the laser at 60 ℃ and 45 mA for a long time to be at least 17 years.