In the China ADS (CIADS) proton accelerator, multipacting is an issue of concern for the superconducting cavities. The parallel codes Omega3P and Track3P, developed at SLAC under the support of the DOE SciDAC program, have been used to calculate the electromagnetic field distribution and to analyze the multipacting barriers of such cavities. In this paper, two types of 162.5 MHz half wave resonator cavities, HWR-010 (cylinder type with β of 0.10) and HWR-015 (taper type with β of 0.15) have been analyzed, and the results of the multipacting analyses show that the resonant electrons occur at different regions with different accelerating gradients. The two-point 1st order multipacting on the short plate has also been researched and discussed.