Integrated slice dependent shimming (iShim) has been found to be able to reduce the magnetic field inhomogeneity and geometric distortion. In this study, we aim to evaluate, optimize and quantify the performance of the in-plane and through-plane geometric distortion in EPI-DWI using iShim. ACR large MRI phantom was scanned in two positions (a: along the bore, b: perpendicular to the bore) to evaluate the in-plane and through-plane geometric distortion. The phantom was separately scanned at 5 GRAPPA acceleration factors (iPAT 1-5) twice. In-plane geometric distortion along phase encoding direction with iShim may be minimized by increasing the acceleration factor.