Effects of the extrusion temperature on the microstructure of solution-treated Mg-2.0Zn-0.5Zr-3.0Gd alloys were investigated by the metallographic microscope, the scanning electron microscope and the transmission electron microscope. Moreover, the mass-loss measurement and electrochemical corrosion technique were used to investigatethe corrosion behaviors of the alloys in the simulated body fluid. The obtained results showed that the extruded alloys were composed of large deformation grains and dynamic recrystallization grains, while the precipitated phases consisted of nanoscale rod-like (Mg, Zn)₃Gd and granular Mg₂Zn₁₁ phase.With an increase of the extrusion temperature in the range of 340 ℃ to 360 ℃, the volume fraction of dynamic recrystallized microstructure of the extruded alloys gradually raised, but the corrosion rates progressively decreased. When the extrusion temperature was 360 ℃, the alloy had a full dynamic recrystallization, and had a better corrosion resistance with a static corrosion rate of 0.527 mm/y, and behaved with a uniform corrosion. When the temperature increased to 380 ℃, a portion of the dynamic recrystallized grains grew abnormally, which resulted in an increase of the corrosion rate with increasing the extrusion temperature.