Abstract: An antibacterial peptide P104 and a lysin LysP53 with broad-spectrum lytic activity and applications thereof are provided. The amino acid sequence of the antibacterial peptide P104 is shown as SEQ ID NO: 1, and the gene sequence of the antibacterial peptide P104 is shown as SEQ ID NO: 3. The amino acid sequence of the lysin LysP53 is shown as SEQ ID NO: 2, and the gene sequence of the lysin LysP53 is shown as SEQ ID NO: 4. The antibacterial peptide P104 and the lysin LysP53 have lytic activity against Gram-negative bacteria, such as Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli The lysin LysP53 can be subjected to soluble expression by Escherichia coli, and the activity of the lysin is high. Therefore, they have good application prospects in the research and development of anti-infective drugs.