Since the inner structure of multi-chamber Helmholtz resonator is complicated, acoustical performance could not be predicted by 1-D plane wave theory. The 3-D acoustical software has been used to simulate multi-chamber Helmholtz resonator which was combined in different ways. Then the influence of different combined structures on transmission loss of Helmholtz resonator was analyzed. The results showed that the parallel or serial structure of Helmholtz resonator could eliminate noise of several frequencies or increase transmission loss in one frequency. The combined series-parallel structure could increase its working frequency range and transmission loss. 