Abstract: A prediction method and system of a low blood pressure is provided, including: obtaining a plurality of feature sequence values; selecting two of the feature sequence values from the feature sequence values according to a time ratio relationship; calculating a relation coefficient according to the selected two feature sequence values by a weighting process; repeating to select the new feature sequence values and the corresponding relation coefficient and to assign the new feature sequence values and the relation coefficient into the input group until the feature sequence values conforming to the time ratio relationship are traversed; and obtaining a training result by substituting the input group into a low blood pressure prediction model.