Abstract: The effects of processing time, temperature, substrate concentration, concentration of H₂SO₄ and particle size by acid-pretreatment of maize stalk using orthogonal design and acid-pretreatment by microwave-acceleration on saccharification process were investigated. The results showed that five factors were the main influence factors and the optimal conditions by acid pretreatment were processing time 2 h, temperature 130℃, concentration of H₂SO₄ 3%, substrate concentration 35 g/L and particle size 0.50 mm. Microwave power can accelerate the effect of acid pretreatment, the sugar yield was almost equal to that of acid pretreatment, and the optimal conditions are as follows: the maize straw powder with the particle size of 0.50 mm and substrate concentration 35 g/L was pretreated in 4% H₂SO₄ at 255W microwave for 60 min.