The invention discloses a water soluble complex formulation type bacteria inhibitor and the preparation method, which comprises extraction of balsam pear, extraction of garlic and extraction of ginger. The invention is characterized in that: three kinds of balsam pear, garlic and ginger respectively having weak and strong inhibition function upon bacteria, mould fungus and yeast are used as raw material to prepare the bacteria inhibitor, thereby effectively spreading inhibition spectrum of bacteria inhibitor and overcoming the failures such as mostly using single plant as raw material and having weaker inhibition result of broad spectrum for prior plant inhibitor. The bacteria inhibitor has the advantages of wider bacterial inhabitation range and better result.