Abstract:This paper described the screening of itaconic acid strain of Aspergillus terreus with UV-irradiation, LiCl treatment and breeding resistant strain to metabolic end product. Breeding resistant strain was an effective measure to help raise yields steadily. A strain, designated At394, producing itaconic acid with a high yield was successfully obtained. The itaconic acid concentration produced by At394 was 53.9 g/L using starch hydrolysate in shaking flasks, which was 42.6% higher than that of the parental strain. The conversion rate was 61.5%, which was the highest value found in tests. The structure determination by infrared spectrum showed the production obtained was itaconic acid.