Using the electromagnetic theory and the method of transfer matrix, a kind of lefthanded material with negative refractive index in 0.3~6.935 GHz microwave band was obtained. The band gap characteristics of photonic crystal consisted of righthanded material and lefthanded materialis were analyzed, respectively. The results show that the band gap of photonic crystal consisted of righthanded material is sensitive to the thickness ratio and the incidence angle, while is not sensitive to the change of period number. To the lefthanded material photonic crystal, the band gap position appears blue shift as the thickness ratio increasing, and the upper band edge of main band gap appears red shift phenomenon as the incidence angle increasing, but the band gap of TE wave is not sensitive to the change of incidence angle. These properties are significance to design omnidirectional reflectorin microwave technologes.