In this paper, the artificial neural network (ANN) was applied to the library search of UV spectra of organic environmental pollutants. The optimization of network parameters was discussed and the effects of noise and impurity were investigated in detail. The use of derivative spectra for ANN library search was proposed to enhance the resolution of the UV spectra. This method could speed up the convergence of the network and could enhance the tolerance of impurity level, but was subject to noise comparing with the ANN using conventional UV spectra. Results show that the ANN is superior to the correlation coefficient method in resistance to noise and impurity.