A new method is presented for silo classification using the rupture plane in the storage. The proposed method is based on the formula of rupture plane orientation determined by the aspect ratio of specified silos and involves the effects of the conical angle of the storage surface, so it can deal with two cases: the conical angle of the storage surface and the flat storage surface. Compared with the two popular methods based on the silo-aspect ratio and the silo rupture plane, respectively, in current engineering design, the new method can give a range of critical aspect ratios to classify deep silos and squat silos according to the conical angle of the storage surface or the fiat storage surface. Moreover, the range covers the critical aspect ratios obtained from the existing classification methods including the Chinese code based on silo aspect ratios, the German code, Reimbert brothers' definition and Liang et al. 's definition, so it is a more general method to classify silos and the existing methods can be viewed as special cases of the presented method.