A turn-by-turn quantization thermal-induced bias error model for fiber coil is established. Based on the model, the effects of the fiber coil with cross winding and quadrupole (QAD) winding on the temperature performance of interferometric fiber optic gyroscope are analyzed comparatively, which shows cross winding coil has more wonderful temperature performance than the QAD winding coil. Furthermore, the traditional spool of the QAD winding coil is redesigned for cross winding coil. The thermal-induced bias error of the new and traditional spool with cross winding coil are analyzed under the same temperature gradient. The results show that the new spool has critical influence to complete optimal properties of cross winding coil, and it can lower the thermalinduced rate error of an order of magnitude, which verifies the theoretical analysis.