Abstract: The recombinant E. coli BL21 （containing recombinant plasmid pGEX-SLP）was induced by IPTG to obtain recombinant fusion protein GST-SLP. This fusion protein was purified by non-specific lithium chloride precipitation and specific Pierce GST Spin Purification Kit purification method. The purified results were identified by SDS-PAGE. The results showed that the target fusion protein with the size of about 71 ku could be purified by using two methods, but the purification effect by lithium chloride precipitation method was less than that of Pierce GST Spin Purification Kit purification method. The study results provided references for further research on the biological characteristics of S-layer protein of Lactobacillus spp..