Y chromosome, male specific, are often used to determine the paternal inheritance. Based on the genetic law of Y chromosome, a method for investigation of Y-STR pedigree has been being established by the Chinese police departments, in assistance to narrow the scope of investigation and determine the family the suspect belongs to. Generally, this kind of method can only be used in enclosed areas, not adequate for open areas, yet be effectively capable of improving the work efficiency. Here, a case was reported that the Y-STR test was used in a new way in a vicious murder case in Suzhou, Jiangsu province, where the Y-STR found the birthplace of the suspect, thereby narrowing the scope of investigation and finally getting the case solved. The way that Y-STR was used here inspired us of a new model of Y-STR application.