High brightness light-emitting diode (LED),a new type of luminescent device,is a perfect substitute for xenon lamp us ed as optical source in differential optical absorption spectroscopy (DOAS) syst em.Spectral shift often influences DOAS retrievals.The effects of temperature an d working current on spectral shift of a blue LED (LZ1-00B205) are discussed,and it is found that the amplitudes of cent er wavelength shift along with the two parameters are respectively +0.025nm/℃ and －0.0032nm/mA.Wavelength shif t and intensity fluctuation on LZ1-00B205are effectively restrained by controlling its temperature constant ( the error is about ±0.1℃) and driving it with a constant current (the current fluctuates within 1%).The blue LED,LZ1-00B205,is used as optical source of long-path DOAS for measuring atmospheric NO₂.The detection limit o f 4×10－9 is obtained for the path length of 760m in the atmosphere.Atmospheric NO_2measurement results are comp ared with those measured by a commercial long path DOAS and the correlation coefficient is 0.98.The experiment al results show that the LED could be available to be light source of long-path DOAS if the emission spectrum is stea dy.The method for improving DOAS retrievals by stabilizing LED spectrum does not need to sample the referenc e spectra,simplifies the procedure of DOAS system and improves measurement accuracy.