The nuclear structure of the actinide even-even thorium isotopes from A=230-234 have been investigated within the framework of the Interacting Boson Model (IBM-1).Predictions are given for the excited state energies for the ground state,β and γ-bands,the transition probabilities between these states,the rotational moment of inertia,and the energy staggering in the γ-band energies.The results of these calculations are compared with the experimental data on these isotopes.