One-dimensional photonic crystals composed of left-handed and right-handed materials are fabricated by using transmission lines (TLs) approach.The transmission properties of the photonic crystals are simulated by the advanced design system (ADS) of Agilent and measured by the vector network analyser.The results indicate that the photonic crystals possess zero-n－gap which exists between the left-handed passband and right-handed passband.The special gap edges are determined by zero average permittivity ε－=0and zero average permeability μ－=0respectively,so it is insensitive to the scale length.