The invention relates to a composite amplification system for simultaneously analyzing multiple Y-STR loci. The composite amplification kit is characterized by compositely amplifying the following 26 Y chromosome loci: DYS19, DYS388, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385a, DYS385b, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, DYS460, DYS481, DYS533, DYS549, DYS570, DYS576, DYS643, DYS449 and Y-GATA-H4. The invention also relates to a method and a kit for simultaneously analyzing DNA samples, and applications thereof.