The paper aims to research the fresh keeping effect of compound biological preservative to prolong the shelf life of cold fresh beef and improve its quality during storage. Cold fresh beef was treated with various biological preservatives and stored at room temperature. The moisture content, pH and TVB-N of cold fresh beef were determined every 3 days. According to the results of single factor experiment, the fresh-keeping agent with obvious effect was selected to form compound biological preservative according to a certain proportion, and the fresh beef was treated to test its fresh-keeping effect. The storage period and quality of cold fresh beef treated with biological preservative were significantly higher than those of untreated samples, and the preservation effect of chitosan, tea polyphenols and lysozyme was more obvious. Therefore, these three preservatives were selected as compound preservatives to treat cold fresh beef, stored at 4 ℃. Its volatile base nitrogen was determined on the 6th day. When the mass fraction of tea polyphenols and lysozyme was 5%, 1% and 3%, the minimum TVB-N of chilled beef was 59.2 mg/kg, which remained fresh. The composite biological preservative has obvious fresh-keeping effect on the cold fresh beef, and can effectively prolong the shelf life of the meat product.