In this paper, genome library of crab Portunus trituberculatus was constructed. By sequencing randomly, 4 164 clones of sequences in the genomic library of crab Portunus trituberculatus were obtained. Then, using software DNASTAR (Version 5. 0) to assembly all of the clones , 709 clones independent of each other, were made in which the length of DNA sequences is about 622 409 bp in total. With the help of the bio-soft Tandem Repeats Finder (Version 2. 02), 130 minisatellites were screened in the crab’s genome DNA sequences. Their cumulative length occupied 2.55% of the total length of DNA sequences. In the minisatellite sequences, twelve-nucleotide repeats were the most frequent type, accounting for 10.77% of the total number of minisatellites. It showed that the number of sequences decreased with the length of its repeat unit（R=-0.663，P＜0.01）. Eight-nucleotide repeat had the largest range of copy number of repeat unit (3.9-66.5), the following were thirteen-nucleotide repeat type (2.0-40.6) and twenty-six-nucleotide (2.3-21.0) , respectively. Descending three repeat types in mean copy number of repeat unit were eight-nucleotide repeat (19.96), twenty-five-nucleotide (16.00) and twenty-two-nucleotide (15.85), respectively. The range of copy number of repeat unit varied from 2 to 66.5, and the copy number mostly ranged from 2 to 25. Moreover, it was showed that the number of corresponding minisatellites decreased as copy number of repeat unit increased. In our research, the 130 minisatellite sequences are composed of 123 kinds of repeat units, so it is very difficult to classify the minisatellite sequences. The minisatellite sequences can be classified into three types: dinucleotide minisatellite sequences composed of two kinds of nucleotide, trinucleotide minisatellite sequences composed of three kinds of nucleotide and tetranucleotide minisatellite sequences composed of four kinds of nucleotide. Further, all of above sequences can be divided into many sub-types according to the composition of nucleotide and their number from large to small. Totally, the minisatellite sequences in Portunus trituberculatus are A/T rich. This paper also discussed the genesis and evolution of minisatellite repeat sequences, and it is belived that the minisatellite repeats may come from the microsatellite repeats. It could be very practical to use minisatellite to study the genome of Portunus trituberculatus and would be applied to a variety of fields.