In order to improve detection of hot water extraction from paper raw material, microwave heating is used in paper raw material test instead of the water-bath heating. Two main factors for efficiency of hot water exaction: irradiation power and time are carefully studied. Experiment results show that when hot water exaction from 2 g straw powder is tested, microwave heating with 400~600 W irradiation power and 4~6-minute irradiation time can achieve the same efficiency as water-bath heating with 180-minute time. Many experiments confirm that microwave heating improves the efficiency of detecting tests greatly and the method is also reproducible.