The invention discloses colibacillus and a method for performing soluble expression of transglutaminase proenzyme thereof. The method comprises the following steps: (1) designing PCR primer to perform PCR amplification according to the nucleotide sequence of transglutaminase proenzyme of streptomyces mobaraensis, cloning the related gene to prokaryotic expression vector pET22b (+),constructing expression vector pET22b-proMTG to conform to E.coli BL21/proMTG of which strain preservation number is CCTCC M 208240; (2) performing soluble expression of transglutaminase proenzyme; (3) activating transglutaminase proenzyme; (4) performing high density fermentation; and (5) performing protein purification technology. In the method of the invention, the yield and specific activity of transglutaminase proenzyme can reach the level of that of transglutaminase proenzyme which is produced by firstly performing direct expression in colibacillus to form inclusion body and then performing denaturation and renaturation and the fermentation process is easier.