La3Ga5.5Ta0.5O14 crystal recently attracted more attention due to its superior electromechanical properties and high Q x f product. We report that the first electron-beam-induced current experiment on La3Ga5.5Ta0.5O14 single crystal. This method is employed to study the effect of the crystal's grain boundary on the incident electron beam. The experimental results clearly show that when the electron beam scans over the grain boundary of the crystal, a fraction of the carriers recombine at the grain boundary and is unavailable for the current generation. This recombination rate will be enhanced when the electron beam was close to the boundary and cause a dip in the collected current. Although the crystal is an insulator, this effect still can be observed if the coating metal is proper to be chosen. It is also pointed out that the different diffusion lengths of the crystal might be due to the tilted grain boundary. (C) 2005 Elsevier Ltd. All rights reserved.