Abstract: In order to obtain bovine prolactin-related protein Ⅰ（PRPⅠ） with high-efficiency expression and analyze it by bioinformatics, the PRPⅠ gene of Holstein cows was amplified by PCR, and then it was linked into the expression vector pET-32 a and transformed into E.coli BL21（DE3） for expression. The expression of the target protein was detected and identified by SDS-PAGE and Western-blot. Bioinformatics methods was used to predict and analyze the structure, post-translational modification and function of PRPⅠ protein. The results showed that PRPⅠ gene was successfully cloned with a size of 606 bp, and a highly purified PRPⅠprotein with a size of 37 ku was obtained by SDS-PAGE and Western-blot.The N-terminal of PRPⅠ protein contained a signal peptide sequence with 36 amino acids without transmembrane structure. A total of 3 N-linked glycosylation sites and 11 antigenic epitopes in PRP Ⅰ protein. PRPⅠprotein secondary structure is composed of α-helix（57.56%）, irregular curl（34.87）,β-folding（5.46）,and extended chain（2.10%）.PRLP,GH1,GHR,SH2 B1,GHE4,GSH2,PRPⅣ,PRPⅥ,PRPⅡ,PRPⅢ proteins interact with PRPⅠprotein.The results indicated that PRPⅠ protein was involved in the regulation of signal receptor activity, cytokine-mediated signal pathways and cell responses to organics and hormones.