Abstract: The evolution of grain structure,grain boundary characterization and texture are studied by EBSD auto analysis technique in an SEM on N18 plates,which were rolled at 750,780 and 820℃,respectively,then cold rolled,and finally annealed at 580℃.The results show that dynamic recovery and recrystallization occur during N18 alloy plates hot rolling and a lot of disfigurements such as low angle grain boundaries and sub-structure are produced.Furthermore,the density of recrystallized nucleation and disfigurements increases with the increasing of rolling temperature.During recrystallization,the density of disfigurements decreases with the increasing of recrystallization time,but still higher than as-received plates,which illustrates that the plates are incompletely recrystallized.The $\{10 \quad \overline{1} 1\}<\overline{1} 0 \quad 12>$ pressure twinning is detected in hot rolling specimens,which illustrates that the pressure twinning can promote the hot rolling deformation in N18 alloy plates.During recrystallization,the density of basal texture decreases with the prolonging of heat preservation time,but the pyramidal texture do not change too much.