By setting up 'benchmarks value' C_j0 of eutrophic state indexes, the 'normalized value' x_j of index value cooespond-ing to 'benchmarks value' C_j0 was taken as the contamination stimulus amounts in the eutrophic state exponential formula based on W-F law. The Weber exponential formula of each index was regarded as equivalence to a Weber exponential pollutant formula with common suited Weber's constant α, because no differences of 'normalized value' x_jl were found on the same class standard of eutrophic state for all indexes. Intellectual Solution Space Search Algorithm ISSS) was used for optimizing Weber constant a in the formula. The optimized universal formula was suited to 14 items of eutrophic indexes. Compared with the results of other methods, it can be used for eutrophic evaluations of dozens of lakes. It showed that the universal Weber exponential formula on eutrophic state had not only solid theoretical basis, but also simple, practical characteristics.