An electronic nose system was developed for detecting beef freshness. An array of gas sensor was selected correctly according to beef smell and sensor experiments. To enhance the sensitivity of electronic nose sensors, purchased sensors were improved. By using the research achievements of biological olfaction, a bionic nasal meatus was designed. In order to improve the recognition rate of the electronic nose system for small samples, appropriate recognition algorithm of support vector machine (SVM) was adopted. Identification experiments of different freshness of beef that had been stored for 7 days were carried out, and results showed that the recognition rate of this system is 99.25%, the feasibility of identifying beef freshness with electronic nose was confirmed.