Abstract: Signal-to-noise ratio(SNR) is a basic concept in seismic exploration.Model-based seismic illumination analysis is an effective method to quantitatively describe the capability of reflection seismic exploration in the design of a seismic observation system.However, few scholars have studied the quantitative relationship between SNR and seismic illumination.Based on the study of traditional ray folds and energy illumination, the concept of seismic SNR illumination was suggested in this paper.The relationships among seismic SNR illumination, folds, and energy illumination were discussed.The influence of the SNR inconsistency on the folds and seismic imaging was analyzed.The functions of SNR, ratio K, average SNR, and coefficient of variation of SNR in seismic acquisition and data processing were discussed.Finally, tests on field data illustrated the effect of seismic SNR illumination on the evaluation of the excitation effect and the design and demonstration of excitation folds of vibroseis.The basic idea of applying SNR illumination to the design and optimization of an observation system was introduced.Folds, energy, and SNR were assumed to be characteristics of seismic illumination.SNR of actual data can be used to compensate for the shortcomings of the folds and energy illumination method.