The invention relates to a salmonella phage, and in particular to a long-tail wide-host-spectrum salmonella pullorum strongly cracked phage. The salmonella pullorum phage is named as SP4, which is preserved in China General Microbiological Culture Collection on July 27, 2017 with preservation number of CGMCC No.14332. The phage is relatively strong in cracking effect on salmonellae; and the phagecan also reduce a death rate of chicks infected by pullorum disease. The preparation (phage) can be independently used or serve as cocktail; therefore, a phage product source, which is safe, free fromtoxic and side effects and free from residues, is provided for the treatment of infection of chicken-source salmonella, duck-source salmonella, mink-source salmonella, food-source salmonella and pig-source salmonella.