A domain-inverted grating is realized by using a scanning electron microanalyzer.Domain inversion in Z- cut LINbO3 by injecting electrons into C- face was Observed. It wasfound that the scanning trace on the crystal surface tended to segment and the inversionwidth near the crystal surface was thinner than that inside the crystal. With different scanrates and beam currents, we get different domain widths and depths. The domain inversionmechanism was also discussed roughly.