The invention provides a predicting method and device for a rupture depth of a marine face shale stratum. The predicting method for the rupture depth of the marine face shale stratum comprises the steps that a first axial pressure and a first confining pressure are applied to each first shale core of at least two groups of first shale cores until the first axial pressure values on the different first shale cores are different, and each first shale core is in a balanced state under the first axial pressure and the first confining pressure; on the basis that the first axial pressure are initial values, the first confining pressures applied on the first shale cores are changed in a decline law; the second confining pressures are obtained and are the confining pressures applied on the first shale cores at the rupturing moment of the first shale cores; and the relation between the axial pressure of the marine face shale and the rupture depth of the marine face shale stratum is obtained according to the second confining pressures, and the number of each group of the first shale cores is greater than or equal to 1. According to the predicting method for the rupture depth of the marine face shale stratum, the influence factors of ground stress on rupture of the marine face shale stratum are considered, and the precision of predicting of the rupture depth of the marine face shale stratum is improved.