Objective To clone,express and purify recombinant OPG/RANKL/TRANCE.Method RNA was extracted from the fetal liver and was reverse transcribed into cDNA.RANKL gene was amplified by RT PCR with designed primers and cDNA as template.The product of PCR were cloned into His tagged expression vector pProEXTM Thc and sent to sequence.Induced by IPTG,recombinant protein of the RANKL was expressed in Escherichia coli stably.The protein was purified by Niion exchange colum.Result Weight of PCR product was 500 bp and sequence of it were correct.Molucular weight of recombinant protein was 20 kD.Conclusion ODF/OPGL/RANKL/TRANCE gene can be amplified simply and conveniently by RT PCR from the cDNA of fetal liver.Recombinant RANKL protein could be obtained by inducing Prokaryotic expression of it.