Abstract: On account of the high residual stress in the near surface layer of the surface-nanocrystallized material by severe plastic deformation,it is rather difficult to prepare the cross-sectional specimens for transmission electron microscopy (TEM) observation. A new specimen preparation method was presented that the specimen was ion milled directly after mechanical pre-thinning. The pre-thinned specimen was glued on a copper ring with Gatan G2 epoxy resin and was cured before ion milling. The points were that the pre-thinning procedure was performed by plane grinding and the specimen and the copper ring was retained by two Teflon plates when the resin was being cured. Therefore,the easy-happened bend of the specimen due to the residual stress was eliminated. The experimental results of TC4 titanium alloy specimens preparation treated by self surface nanocrystallization showed that the specimens had no bending deformation and had large cross-sectional thin area. The subsequent TEM observation of the specimens was achieved successfully.