The firing process plays a crucial role on the microstructures of sol-derived YBa2Cu3O7-x (YBCO) films; thus, it affects the critical current density, A, of the films. In this paper, the effect of the oxygen partial pressure temperature (P-O2-T) combination during the firing process on the microstructure and J(c) of an YBCO film derived from a low-fluorine sol-gel method was investigated. The results indicate that the optimal P-O2-T combination for a high-J(c) YBCO film is different from that derived from an in-situ deposition reported previously. When the optimal P-O2-T combination is adopted, the resulting YBCO films exhibit good biaxial texture characteristics and dense surfaces over the entire firing temperature range of 700-775 degrees C. In addition, the YBCO films exhibit a J(c) of above 2 MA/cm(2), even though they are fired at 700 degrees C. Moreover,A is near 10 MA/cm(2) for the YBCO film fired at 775 degrees C. (C) 2015 Elsevier B.V. All rights reserved.