The bandgap properties and localized defect mode of one-dimensional ternary photonic crystals with negative-index materials are investigated by optical transfer matrix method.The results show that a new type of omnidirectional gaps is found.In contrast to the Bragg gaps,the properties(the central frequency and width of the gap) of such omnidirectional gaps are insensitive to the incident angles.When a defect layer is introduced,a defect mode appears inside the omnidirectional gap,and the spectral position of the defect mode is almost independent of incident angles and nearly invariant with the scaling.