Gayageum and Geomungo are the traditional stringed music instrument in Korea. These strings are usually made of raw silk. This study was carried out to investigate the optimum condition for silk string producing method using several kind of silk and setting temperature of silk string. If the ply of strings and twisting condition were same, tenacity and elongation of every silk strings were similar, in spite of silk strings prepared by physically different raw silk. On the other hand, in setting treatment of twisted string, it was disclosed that the proper setting temperature of silk strings were 11$0^{circ}C$ for 20 min.