This research is based on a computational study of a [1,3] sigmatropic intramolecular hydrogen rearrangement for (Z)-3-(4-(dimethylamino)benzylidene)thiochroman-4-one, applying the Density Functional Theory with the exchangecorrelation functional B3LYP and 6-31G(d,p) set basis using software package Gaussian 09W. Two possible suprafacials and anatarafacials migrations of the hydrogen atom bonded to ring thiopyran-4-one of the (Z)-3-(4-(Dimethylamino)- benzylidene)thiochroman-4-one were evaluated, results show an activation energy of 4 Kcal/mol which is more favorable for a transition state featuring characteristics related to a [1,2] suprafacial shift, in comparison with the amount of activation energy of a [1,3] antarafacial shift transition state.