beta-Ga2O3 nanowires have been synthesized at a low temperature of 550 degreesC using a single precursor of gallium acetylacetonate through the vapor-liquid-solid (VLS) mechanism. Synthesis of very thin beta-Ga2O3 nanowires with an average diameter of 8 nm was achieved using this method. The influences of substrate temperature, pressure, and Ga vapor concentration on the growth and the diameter distribution of beta-Ga2O3 nanowires were investigated in this work. It was found that the diameters of the Ga2O3 nanowires are also affected by the growth conditions, in addition to being correlated to the diameters of the initial An catalysts on the substrates.