In this study, the random amplified polymorphic DNA( RAPD) technique was used to analyze the genetic variation among the allotetraploid hybrid of red crucian carp ( Carassius auratus red var. , .. ) .. common carp( Cyprinus carpio L. .. ) , red crucian carp and common carp. One hundred 10..nucleotide..long random primers were used in the RAPD analysis. Of these primers, 60 primers produced well..amplif ied and reproducible band patterns. There were 6 to 20 bands ranging in size from about 200 to 3 500 bp in the amplified products of a single primer. After excluding bands that were not clearly identifiable, a total of 1 554 distinguishable fragments were compiled for phylogenetic relationship analysis. The genetic similarity index of the amplif ied DNA bands between the allotetraploid hybrid and their original maternal red crucian carp was 69. 41 % , and the genet ic similarity index of the amplified DNA bands between allotetraploid hybrid and their original paternal common carp was 64. 47 % . The similarity index of the amplif ied DNA bands between red crucian carp and common carp was 42. 18 % . Moreover , 4 specif ic bands were found only in the allotetraploid hybrid, the non..parentage bands ratio of the allotetraploid hybrid was 0. 72 % . The results not only provided the specific molecular markers of the allotetraploid hybrid , but also demonstrated that the allotetraploid hybrid inherited a little more genetic materials f rom their original maternal red crucian carp than their original paternal common carp.