Abstract: Objective: To clone the cDNA of sus scrafa mature peptide of bone morphogenetic protein-4. Methed: Totle RNA was extracted from kidney of sus scrafa and the desired segment was obtained by RT-PCR with two specific primers.The PCR products was cloned into pMD18-T vector and transformed into Top-10 competent cells. After PCR and double enzyme screening, the sequence of insert in the recombinant plasmid was assayed by DNA sequence machine. Results: DNA agarose electrophoresis showed that the products of RT-PCR was consistent with desired BMP-4. PCR, double enzyme digestion revealed that the PCR product was inserted pMD18-T vector and sequencing demonstrated that the mature protein cds of pig BMP-4 was consisted of 351 nucleotides and encoded 116 amino acids. Sequence alignments showed that the mature protein cds of pig BMP-4 had 94.87%, 90.60%, 94.87% and 94.59% homologies with that of human, mouse, cow, and sheep respectively, while the homologies for the deduced amino acids were 99.12%, 99.12%,100% and100% respectively. Conclusion: It is concluded that the mature protein cds of pig BMP-4 have been successively cloned, and this will promote the further studies on the full gene structure and function of this gene as well as its relationship with pig reproduction.