The invention provides a yarn used for a sweater, which consists of the following components by weight percentage: 35 to 45 percent of wool fiber, 35 to 45 percent of modal fiber and 15 to 25 percent of pearl fiber. The invention also provides a method for producing the sweater by using the yarn. The invention reasonably set the weight ratio of each fiber according to the characteristics of different fiber raw materials to show the property of each fiber, integrates the advantages of the various fibers, keeps the fundamental characteristics of the sweater, has the functions of resisting ultraviolet shielding, quickens human body microcirculation, promotes metabolism, can protect the skin from being damaged by ultraviolet radiation, and has certain health care and protective functions to a human body. The yarn can be manufactured into in spring clothes, summer clothes and winter clothes, and is comfortable and easy to wear and good in property.