In order to find a convenient and efficient way to measure the freshness of fishmeal，on the basis of volatile odor of storage fishmeal，four-gas sensor arrays（TGS822 for ethanol，TGS825 for H2S，TGS826 for NH3 and aime，TGS832 for halocarbon） were selected as the nose of the electronic nose system．An electronic nose system based on portable data acquisition device of USB standard and LabVIEW was constructed．The number of storage days of fishmeal was detected by electronic nose and semimicro-kjeldahl determination．Cluster analysis of fishmeal was studied through principal component analysis（PCA）．The results show that different freshness of fishmeal can be clustered well，which proves the applicability of electronic nose measurement system．