In this paper, we proposed a novel method to upgrade the acid-rich phase of bio-oil via ketonic condensation over weak base catalysts. Most acetic acid could be transformed to acetone in model reactions, and CeO2 was proved to be suitable as an active phase for catalyzing this reaction. The effects of water and three model components (phenol, p-methoxyphenol, and frufural) on acid transformation over four CeO2-based catalysts were investigated. As a result, with feeds containing water and phenols with liquid hourly space velocity (LHSV) of 4 cm(3) g(-1) h(-1), this reaction could proceed efficiently and adequately. However, furfural deactivated catalysts significantly, and therefore, furans must be treated before this transformation.