The effect of two kinds of constitutive strong promoters P43 and PlapS on regulation of heterologous gene was compared on the expression level of ZEN degrading enzyme gene ZLHY6 and the enzyme activity evaluation. The degrading enzyme gene regulated by PlapS received efficient expression in bacillus subtilis 168, and the degrading enzyme activity reached the highest level of 219.02 U/mL after fermentation for 12 h. Moreover, the genetic stability of ZEN degrading enzyme gene expression vector pWBZ7 regulated by PlapS in Bs 168 lays a foundation for efficient expression and secretion of degrading enzyme.