Catalytic deoxygenation co-pyrolysis of bamboo wastes and microalgae with biochar catalyst was investigated in a fixed bed reactor to explore the deoxygenation effect and possible deoxygenation mechanism of biochar catalyst (resulted from bamboo wastes pyrolysis). Results showed that oil fraction yields from co-pyrolysis of bamboo wastes and microalgae decreased largely with biochar addition, but still maintained at 35-37 wt.%, while gas yields were enhanced greatly. As catalytic co-pyrolysis promoted the decomposition of long-chain fatty acids and 0-species, and the formation of aromatics and phenols, therefore most oxygen in bio-oil vapor transformed to CO, CO2 and H20, and only 7-9 wt.% oxygen retained in oil fraction. It indicated that biochar catalytic co-pyrolysis could not only efficiently remove oxygen (over 90 wt.%), but also keep oil fraction yields. Moreover, the active 0-containing groups and specific surface area of biochar catalyst decreased largely after catalytic co-pyrolysis. The possible reaction pathways of catalytic co-pyrolysis with biochar catalyst were proposed. (C) 2018 Elsevier Ltd. All rights reserved.