Abstract: The Doebner and Gieseke's method of synthesizing cinchophen was modified and further developed. In condensing 1.25 moles of benzal aniline with 1 mole of crude 50% pyruvic acid at 40℃ in alcohol, the yield increased up to 60.20% of the theory. The production of pyruvic acid was made more economical and convenient by dry distillation of tartaric acid in higher temperature.