In the framework of the Blonder-Tinkham-Klapwijk model，we calculate the differential tunneling conductance in normal metal / insulator / normal metal/triplet p-wave superconductor junctions which is studied theoretically as a function of the bias voltage. The results show that there are zero-bias conductance peak, zero-bias conductance dip, double-minimum structures and oscillation components of the differential conductance in the spectra for p-wave superconductor junctions. It can be seen that additional current steps appear in the I-V relationship. The existence of such structures in the conductance spectrum may serve as an evidence that the pairing of Sr2RuO4 has p-wave symmetry.