As the fist step for the genetic analysis in the silkworm, associations between GC content of primer and detectable amplification products using AP-PCR were investigated. PCR products were not detected in the random primer of 40% GC content level. In the 50% level, amplification strengh was 75.5% (bad amplfication), 11.1%(poor amplification) and 11.1% (good and excellent amplification). According to increasing GC content of random primer, however, PCR products showing polymorphisms increased highly to 22.5%, 50% and 91.6 in the 60%, 70% and 80% GC content, respectively. And by digesting the template, prior to performing PCR, with four and six base cutter, RAPD profiles from certain primers were not affected by this pretreatment of the template, but other primers produced distinct profiles from each of several restriction endonuclease assayed. From these results, we estimate that random primers of above 60% GC content and predigested template will be selected in considering of time and cost of primer to study indentification, linkage mapping and genetic variation in the silkworm using AP-PCR.