Antimicrobial chitosan biguanidine was prepared for meat and poultry packaging using chitosan and dicyandiamide as raw material. The preparation process of chitosan biguanidine was optimized using orthogonal experiment method. It was found that when HCl concentration is 0. 4 mol / L, mole ratio of functional group is 1 : 5, and the reaction time is 20 min, the best yield is 92. 96% . The product was characterized by FTIR and the result showed that the nucleophilic addition reaction of the amino-group of chitosan and the cyano-group of dicyandiamide has been done and the product is chitosan biguanidine. The results of antibacterial test showed that the antibacterial activity of chitosan biguanidine is obviously better than chitosan, and also the antibacterial activity against S. aureus is better than E. coli. The inhibition rate of the antibacterial film with 10% chitosan biguanidine against E. coli and S. aureus is 95. 67% and 97. 45% respectively.