The effect of aging temperature on the magnetic properties has been studied. The magnetic measurement results indicate that the remanence decreases with increasing aging temperature Ta，and the coercivity has a maximum value at Ta=690℃. After the first aging， the degree of ordering increases with Ta， which shows that the grain size of ordered phase also increases. This is the reason for the change of the coercivity. After the second aging， the microstructure does not change and the anisotropy field of ordered phase increases， which leads to an increase in the coercivity.