Ultrasonic microwave-assisted extraction of oligosaccha-rides from lotus (Nelumbo nucifera Gaertn.) seeds (LOS) was investigated. The five parameters, ultrasonic time, ultrasonic temperature, microwave power, microwave time and solid to liquid ratio were optimized using the Box-behnken design with a quadratic regression model built by using Response Surface Methodology (RSM). The highest oligosaccharide yield, (10.525±0.017)%, was obtained under optimal conditions for ultrasonic time, ultrasonic temperature, microwave power , liquid to solid ratio and microwave time at 10 min, 45 ℃，100 W，100 min and 301 (mL/g), respectively.