Abstract: Fish freshness decreases during storage and a series of characteristic odor emits.Gas chromatographymass spectrometry (GC-MS) was used in this research to test fish stored at 4℃ and the characteristic volatile compounds during decay were analyzed.Sensors which were sensitive to these compounds were screened, and a sensor array was structured using these sensors.An electronic nose based on this array was used to verify the validity of this array for evaluation of fish freshness by taking Parabramis Pekinensis as samples.Results showed that the volatile compounds were confirmed to be alcohol, aldehyde, ketone, hydrocarbon, benzol, acid, and compounds with N and S.Corresponding to these compounds, TGS822, TGS2620, TGS880, TGS813, TGS816, TGS832, TGS831, TGS2610, TGS2611, TGS2600, TGS826 and TGS825 were screened and a sensor array was structured.An electronic nose based on the sensor array was used to detect fish samples.PCA and FDA were employed to analyze the experiments data.Results showed that the first three PCs could explain 95.6% of the variance, and samples of different freshness grades were well separated.This research proved that the gas sensors screening method developed was very effective and it provided fast response and high accuracy on fish freshness evaluation.