The invention provides a method for detecting a plurality of residual pesticides in tobacco simultaneously. The method is characterized by carrying out sample pretreatment by an ASE (accelerated solvent extraction) device so that extraction and purification are realized through one step, wherein a florisil and graphitized carbon black (GCB) mixture is added to an accelerated solvent extraction tank at the bottom of which a filter membrane is arranged; next, a mixed sample, which is a mixture of powdered tobacco and kieselguhr, is added to the accelerated solvent extraction tank; in succession, an interior label is added and the unoccupied space above the extraction tank is fully filled with the kieselguhr; after extraction is finished, the extracts are mixed evenly and filtered through a 0.22-micron organic phase filter membrane; finally, liquid chromatography-tandem mass spectrum (LC-MS/MS) detection is carried out. The method provided by the invention is capable of completing the extraction and purification of the sample through one step so that the pretreatment process is greatly simplified; the detection method is high in automation degree, simple to operate, high in sensitivity and accuracy, and good in repeatability; the method is capable of detecting as many as 92 residual pesticides in the tobacco simultaneously, and meets the requirements of a multiple-residual pesticide analysis method.