Protein expression technology, also known as recombination or fusion protein technology, refers to the process of obtaining target proteins through genetic engineering. The recombinant protein expression technology is divided into two main aspects: the expression of target proteins and the purification of target proteins. The expression of recombinant proteins is divided into multiple expression systems, and the basic techniques of these expression systems are relatively mature. We have a mature protein expression platform, including prokaryotic expression and yeast expression systems and downstream recombinant Protein purification technology.