The invention relates to the field of processing of dairy products, and specifically relates to low-fat cheddar cheese containing lactobacillus casei generating exopolysaccharides and a preparation method of the low-fat cheddar cheese. Under the condition that any fat substituents and glue additives are not added, the defect that character and fusing property of low-fat cheddar cheese are poor due to lipopenia is improved by means of natural exopolysaccharide generating bacteria, and the low-fat cheddar cheese approaches whole fat cheddar cheese. The fat content of the low-fat cheddar cheese provided by the invention is reduced by over 50% compared with a normal whole fat group. The cheese prepared by the invention is not only low in fat content, but also is easy to accept by consumers in character and taste. The product is suitable for crowds and children with obesity and diabetes to eat. In addition, the cheese is beneficial for preventing diseases such as obesity and cardia-cerebrovascular diseases for common crowds.