The cDNA coding region of FBLN5 of sika deer was cloned to investigate the function of FBLN5 in antler regeneration. RT-qPCR was used to analyze the sequence and using bioinformatic tools RNAi vectors of FBLN5 were constructed to down regulate the FBLN5 gene expression in PPP cells. Conditioned medium both from down regulated and negative control groups were made and added to HUVEC cells to test the biofuntion of FBLN5 in PPP cells by MTT assay. The results revealed that: 1. The length of cDNA of FBLN5 is 1347 bp, which encodes a protein of 272 amino acids. 2. Bioinformatics predicts that FBLN5 is a hydrophilic protein with one transmembrane region and a signal peptide including 23 amino acids. FBLN5 has three kinds of domains: vWA_Matrilin, cEGF and EGF_CA. We predicted the tertiary structure of sika deer FBLN5. 3. The RNAi sequence pLVTHM-FBLN2 was most effective. It down regulated the expression of FBLN5 in PPP cells by up to 88.72%. MTT assay revealed that the proliferation of HUVEC cells was stimulated by up to 35.7% as cultured with whole conditioned medium of pLVTHM-FBLN2 group in construct with negative control group. We concluded that FBLN5 may be involved in angiogenesis and homeostasis in the process of antler regeneration