Theoretical studies of the intermolecular potential energy surfaces (PESs), the intermolecular vibrational states and the wavefunctions for the C3-Ar complex have been performed at the CCSD(T) level with four different basis sets,. Each PES can be characterized by two symmetrical T-shaped global minimum at ɵ = 75° and ɵ = 105°, a saddle point between them at ɵ = 90°, and two collinear saddle points at ɵ = 0° and ɵ = 180°. Moreover, we also calculated the intermolecular vibrational frequencies and the average structural parameters of the ground vibrational states for the C3-Ar complex. The vdw bending and stretching frequencies are calculated to be 8.682 and 34.511 cm-1, which are in agreement with the experimental results and a more accurate result was determined for the bending mode. Studies show that the larger the basis set is used, the more accurately the results are calculated.