The flow stress behaviors and microstructure characteristics of 690 alloy were investigated by isothermal compression tests in the temperature range of 1050-1200 °C and strain rate range of 0.1-10 s-1 on Gleeble 1500 thermo-simulation machine. The flow stress constitutive equation and dynamic recrystallization model of 690 alloy during hot compression was established. The results show that the flow stress can be represented by a Zenner-Hollomon parameter in the hyperbolic sine type equation. The flow stress of 690 alloy predicted by the proposed models well agrees with experimental results. Therefore, the proposed model can provide the references for the microstructure control during hot extrusion process