The temperature dependence of exchange bias and coercivity of ferromagnetic layer and antiferromagnetic gain layer is discussed. In this model, the temperature dependence comes from the thermal instability of the system state and the temperature modulated relative magnetic parameters. These numerical results show that, at low temperature, the exchange bias and the coercivity decrease with increasing temperature, but the exchange bias becomes flat with increasing interface exchange coupling or decreasing ferromagnetic anisotropy. However, at high temperature the exchange bias become zero while the coercivity reach a peak, which are in good agreement with experimental results qualitatively. Based on our discussion, we can conclude that a soft ferromagnetic layer coupled by a hard antiferromagnetic layer with special exchange coupling may be very applicable to design magnetic devices, which with high exchange bias and low coercivity and almost independent of temperature.