Abstract: The fermentation conditions for Glutamic acid production by a mixed starter culture composed of Aspergillus oryzae and Monascus purpureus in solid state fermentation were optimized. The effects of fermentation time, fermentation temperature, medium initial p H and moisture content on Glutamic acid were studied by single factor and orthogonal array design methods.Results suggested that the optimal fermentation conditions were the fermentation temperature 32 ℃, the fermentation time 5 d, the initial p H of fermentation medium 6 and the moisture content in medium 30%. Under these conditions, the yields of Glutamic acid and total amino acids were 194.2 g/kg and 768.5 g/kg, respectively, which were increased by 15.7% and 5.5%respectively compared to that before optimization.