Based on the quick start-up of fiber optic gyro(FOG) requirement is increasing for the inertial navigation system and the modern weapons, the start-up wavelength drift of superluminescent light emitting diodes(SLD) was studied, which is the slowest start-up core device in FOG. The relationship between SLD output wavelength with drive current and temperature was analyzed and verified both in theory and experiment, it was obtained that the wavelength decreases about 0.15 nm/mA with the increase of drive current and increases about 0.5 nm/°C linearly with the increase of the temperature; The start-up model of SLD wavelength change was established by the changing law of the driving current and the core temperature of SLD after starting-up, and it was inferred that the max wavelength change was 18 000 ppm by the measurement of SLD drive current and temperature; Finally, the wavelength compensation solution was proposed to realize the quick start-up of FOG.