Abstract: Microwave-vacuum experiments of Pleurotus eryngii were conducted in order to improve the quality of products and decrease the drying energy consumption. The effects of microwave power density (X1), material thickness (X2), absolute pressure chamber (X3) and the interaction of these three factors on color (Y1), rehydration ratio (Y2), amino acids (Y3) and unit energy consumption (Y4) were investigated in this study. The process parameters were optimized through the quadratic orthogonal rotary combination design with three factors and three levels. Linear weighting method was used to analyze comprehensive multi-objective optimization. The regression equations of four indexes were developed based on the experimental data and the optimal combination in process were obtained. The results showed that there were significant impacts of color, rehydration ratio, amino acids of Pleurotus eryngii and unit energy consumption from power density, material thickness and absolute pressure chamber. The major factor affecting on the color of Pleurotus eryngii was material thickness. The color of Pleurotus eryngii was poor when material thickness was less than 2 cm. The major factor affecting on rehydration ratio and amino acid of Pleurotus eryngii was absolute pressure chamber. The smaller absolute pressure chamber was beneficial to rehydration of dried Pleurotus eryngii and reduced the loss of amino acid of Pleurotus eryngii during drying. Microwave power density was the major factor affecting on the unit energy consumption. The energy consumption was high when Pleurotus eryngii was dried at high microwave power density. The combination of high microwave power density and small absolute pressure chamber could cause even higher energy consumption. The microwave power density of 12.5 kW/kg, material thickness of 2.4 cm and absolute pressure chamber of 18 kPa were the optimized parameters of microwave-vacuum dried Pleurotus eryngii with high-quality and low-energy consumption. Their product quality was excellent, the color was white (the value of color difference was 78), rehydration ratio (1.58) was appropriate, amino acids (473.1 mg/100 g) was less damaged , and unit energy consumption (9.3 kJ/kg) was lower.