The dynamical potentials of highly excited vibrational states of HOCl in the bending and OCl stretching coordinates with anharmonicity and Fermi coupling are studied. The result shows that HO stretching vibration mode has significantly different effects on OCl stretching mode and HOCl bending mode under different polyad numbers. The dynamical potentials and the corresponding phase space trajectories are studied in the case that the polyad number is 24 and it is found that the quantal vibrational energy levels could be classified by the fixed points of dynamical potentials and the quantum environments could be identified by the numerical values of action integrals.