Two structures of left handed metamaterials were proposed. Using numerical simulation, the S parameters for the two structures were calculated. Because the electromagnetic fields in conducting metamaterials can be localized to regions much smaller than the incident wavelength, it can be difficult to perform accurate numerical simulations. To obtain greater numerical accuracy， finite integration technique (FIT) was used. The results show that the wire symmetry breaking affects the resonant frequency and passband for SRR owing to the coupling between wires and SRR.