It designs a way that can easily screen high-pyruvate-producing strain. It is a intelligently selected method which can highly improve the efficiency of strain screening. The principle can be described as the following: On the CaCO₃ medium, a transparent ring can be exhibited based on the reaction of PYR produced by the strain and CaCO₃ in the medium for pyruvate-calcium is a kind of soluble substance, it is obviously that the high-pyruvate-producing strain has a bigger dimension of the transparent ring. On the other hand, color reaction between TTC and ADH indicate the enzyme activities which have a proportional relation with color, our object strain is a weak-ADH-enzyme- activities type with a weak metabolic flux from PYR to alcohol. So the white color strain may be the right choice.