The invention relates to a three-phase cable transient temperature rise obtaining method for duct laying independent of skin temperature. The method comprises the following steps of 1) building a three-phase cable thermal circuit model of duct laying; 2) according to the three-phase cable thermal circuit model of the duct laying, obtaining a three-phase cable transient temperature rise calculationmodel of duct laying, and determining parameter values in the three-phase cable transient temperature rise calculation model; and 3) obtaining a three-phase cable transient temperature rise by adopting the three-phase cable transient temperature rise calculation model. Compared with the prior art, the method has the advantages that the temperature rise of an outer sheath and the temperature riseof a cable core are considered, the application range of the model is expanded, the calculation is easy and quick, and the verification is easy, and the like.