The uniplanar compact photonic_bandgap (UC_PBG) is a periodic planar layered str ucture which is constructed in the microstrip structures. In this paper, the sub strate is regarded as an uniaxial anisotropic medium, and the UC_PBG is analyzed using the method of lines (MoL). The process of MoL is described in detail, som e UC_PBGs with different dielectric parameters are computed. It is shown that th e complete band gaps or even larger ones appear in dispersion diagram of those UC_PBGs.