Objective To produce the standard allelic ladder by using the cloning technique. Methods After the amplification and separation of the STR alleles, they were purified and then connected with T-vectors directly. The combinants were transfected into the component E. coli DH5? cells follwed by cloning and plasmid purification. The allelic ladder were then produced by re-amplifying the recombinant plasmid DNA. Results The allelic ladder made in this way can be produced in a lager amount and can be stored in a relatively long period. Conclusion The results demonstrated that the standard allelic ladder generated in this way is more practical in forensic scienc application. This technique in useful for preparation of domestic STR kits.