If the expression protein with certain activity is needed, it is better to express the protein soluble form to avoid the inclusion body formation. To avoid many, such as: the method of inclusion body expression system is not high, choose help soluble expression of fusion systems such as pThio, pMal and so on, for the T7 system to reduce or reduce the induction conditions (such as reducing the concentration of ITPG decreased expression of T7 polymerase) so as to reduce the speed, using the basic culture medium also has contribute to the soluble expression. Another problem which is easy to be overlooked is that the reduction of two sulfur bonds can not be correctly formed in Escherichia coli, which is also likely to cause insoluble expression products. Replacing strains such as Novagen's Origami series also helps solve this problem. Another way is when protein is hung on a column, when the glutathione is reduced and oxidized, the guanidine column from 6M to 0M is used to promote protein folding. After the refolding of the protein, the protein was eluted with imidazole. The expression of the supernatant protein through the method of detai service condition matrix orthogonal optimization, the expression of recombinant protein in the supernatant, the expression protein was obtained with considerable activity