The invention discloses an extraction and purification method of secretory immunoglobulin A and secretory component protein in sow colostrum. By means of the extraction and purification method, the purification step of the secretory immunoglobulin A in the sow colostrum is simplified, after salting out is conducted step by step, gel is selected directly for filtration, a column for filtering the gel is Superdex 200 Increase 10/300 GL, it is proved through follow-up western-blot experiments and mass spectrometry experiments that pure immunoglobulin A can be obtained through the method, the process for purifying the immunoglobulin A in the sow colostrum is simplified, the production cost is reduced, and the production efficiency is improved. Meanwhile, after the salted-out colostrum is subjected to polyacrylamide gel electrophoresis, it is determined that protein of which the molecular weight is about 80 KD is the secretory component protein. In this way, more secretory component protein can be obtained.