The bending effects of single mode fiber, polarization maintaining fiber, photonic crystal fiber and polarization maintaining photonic crystal fiber on fiber optical gyroscopes (FOG) performance are analyzed. A comprehensive model is established, and then based on high-precision FOG application, the power, spectrum width, and mean wavelength after transmitting sample fibers are measured by using the erbium-doped superfluorescent fiber source when changing the bend radius. Based on the measured data, the scale factor stability and random walk coefficient of FOG are calculated. The results show that bending effect of photonic crystal fiber is very small and can be neglected in FOG, while the bend radius should be controlled when using other two conventional fibers.