he mitochondria) DNA(mtDNA)of silver carp were digested by 11 restriction endonucleases which were Bam I，Bgl I，Bgl B，EcoR I，Hpa I，Kpn I，Pst I， Sac I，Sal I，Xba I and Xho I .The fragments cleaved by these enzymes are 3，4，0，4，2，1， 1，1，0，2 and 1，respectively. The mtDNA of bighead were digested by restriction endonucleases Bgl I，Bgl B，Hpa I，Rpn I，Pst I，Sac I，Sal I，Xba I and Xho I into 4，1， 2，1，1，3，1，2 and 1 fragments，respectively. The sizes of mtDNA were estimated by agarose gel electrophoresis and they are 15930士220 by for silver carp and 16650士150bp for bighead. The maps of 9 restriction endonucleases for silver carp(18 cleaved sites)and bighead(16 cleaved sites) were constructed after digesting by the single，double or partial enzyme. The paper also compared the enzyme-digested sites，the size of fragment and the maps of restriction endonucleased between both fishes.