Fiber optic gyroscopes (FOGs) are widely used in attitude control systems of spacecraft such as satellites and Mars rovers for their superior spatial adaptability. However, changes in ambient temperature can cause errors in the FOG and reduce its output accuracy. In this paper, a fuzzy two-stage temperature control strategy applied to a satellite-borne three-axis integrated fiber optic gyroscope (TAIFOG) is proposed. And the control rules of the fuzzy two-stage temperature controller are described in detail. A thermodynamic model that can quickly and accurately respond to the dynamic thermal characteristics of the satellite-borne TAIFOG is also constructed based on the lumped method. The effectiveness of the proposed fuzzy two-stage temperature control strategy in improving the temperature stability of the satellite-borne TAIFOG in orbit is verified through numerical studies. Numerical results show that this fuzzy two-stage active temperature control strategy can fundamentally improve the thermal state of the satellite-borne TAIFOG and ensure that its sensitive element fiber optic coils maintain high-temperature stability while the TAIFOG is in orbit. In addition, the startup time of TAIFOG is reduced to 308 s compared to the case without active temperature control, which is a reduction of 96.27%. This active temperature control strategy is well suited for engineering applications to improve FOG output accuracy.