The dual-polarization interferometric fiber optic gyroscope (IFOG) has been studied for many years and achieved remarkable performance. In this study, we propose a novel dual-polarization IFOG configuration based on a four-port circulator, in which the polarization coupling errors and the excess relative intensity noise are well handled meanwhile. Experimental measurements of the short-term sensitivity and long-term drift using a fiber coil with a length of 2 km and a diameter of 14 cm show that the angle random walk of 5.0×10-5∘/h and bias instability of 9.0 × 10-5 °/h are achieved. Moreover, the root power spectrum density of 20n r a d/s/H z is almost flat from 0.001 Hz to 30 Hz. We believe this dual-polarization IFOG is a preferred candidate for the reference-grade performance IFOG.