Nicotine is extracted from discard tobacco by microwaveassisted extraction method, and the nicotine content in the extraction solution is detected by high performance liquid chromatography. The ethanol concentration, ratio of material to liquid, microwave power, microwave radiation time and extraction temperature are studied to get the optimal technique condition for nicotine extraction. The results show that the optimal conditions for microwaveassisted extraction are as follow: the ethanol concentration is 60%, the ratio of material to liquid is 1〖DK〗∶45, microwave power is 320W, microwave time is 6 min, and extraction temperature is 50℃, under which the extraction rate of nicotine is up to 89.2%. The method has the qualities of rapidness, precision, energy efficiency, environmental protection, wide suitability, etc.