The model based on the idea that the p$_y$-orbital of the carbonyl oxygen is responsible to receiving hydrogen was devised for simulation of intramolecular hydrogen transfer. A Monte Carlo method was applied to free rotation of a molecular chain performed by changing the dihedral angles, and a "hit" was defined as the case when the migrating hydrogen comes within the region defined as the p$_y$-orbital and satisfies all the geometrical requirements for abstraction. A set of parameters was employed for defining the region and the requirements; $ au$ was defined as the angle formed between O...H vector and its projection on the mean plane of the carbonyl group (- 43$circ$ < $ au$ < + 43$circ$), $Delta$ as the C=O...H angle (90 -15$circ$ < $Delta$ < 90 + 15$circ$), $ heta$ as the O...H - C angle ( 180 - 80$circ$< 0 < 180 + 80$circ$), d as the distance from the center of the lobe of the p$_y$-orbital to hydrogen (0 < d < 1.04 ${AA}$). The minimum value for the distance between carbonyl oxygen (O$_1$) and the migrating hydrogen (H$_i$) and for that between non-bonded atoms except the pair of O$_1$ and H$_i$ were assumed to be 0.52 ${AA}$ and 1.54 ${AA}$, respectively. The apphcation of this model to intramolecular $eta$-, $gamma$-, $delta$-, $epsilon$-, and $zeta$-hydrogen abstraction in ketones and $eta$- and $ heta$- proton transfer in oxoesters gave good results reflecting their photochemical behavior. The model was also used for prediction of photoreactivities of 2-(N,N-dibenzylamino)ethyl 2-, 3- and 4-benzoylbenzoate (1a - c). (1a - c).