YBa2Cu3O7-x (YBCO) films with different thicknesses were fabricated on buffered Ni-W tapes by pulsed laser deposition. The thickness dependences of microstructure and critical current density (J(c)) of YBCO film were systematically investigated. The microstructure and surface morphology of YBCO film were characterized by X-ray diffraction, optical microscopy, field emission scanning electron microscopy and atomic force microscopy. And the critical current (I-c) of YBCO film was measured by the conventional four-probe method. We found that the full width at half maximum values of both omega and phi scan rocking curves, the content of a-axis oriented grain, and surface roughness of YBCO film all increased with augmenting the thickness of YBCO film. It was also found that with increasing the thickness of YBCO film from 0.3 mu m to 1.5 mu m, the I-c of YBCO film increased from 72 A/cm to 248 A/cm and yet J(c) of YBCO film decreased from 2.1x10(6) A/cm(2) to 1.6x10(6) A/cm(2). Our results indicated that the microstructure and J(c) of YBCO film were largely dependent on the thickness of YBCO film under the optimized deposition condition of substrate temperature. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.