Co-pyrolysis of biomass and oil shale to produce oil can solve the problems of low shale oil yield and high oxygen content of bio-oil, which considered both oil yield and quality with a positive synergy. The co-pyrolysis oil with high economy can be used as an alternative energy source for petroleum after refining, and further alleviate the oil shortage in China. Based on the above background, the research progress on co-pyrolysis of biomass and oil shale was reviewed. Firstly, the pyrolysis characteristics of oil shale and biomass were discussed, respectively. Then the effects of biomass raw materials and pyrolysis temperature on the co-pyrolysis process and product characteristics were clarified, especially the significant effect of secondary reactions on product distribution due to the excessive pyrolysis temperature. On this basis, the free radical release-binding mechanism, five alkali/alkaline earth metal catalytic mechanisms and various types of mineral catalytic mechanism were summarized. The synergy mechanism were explained as a result of the combination of free radicals and the multiple catalytic behavior. Finally, based on the research status, the future prospects of biomass-oil shale co-pyrolysis were proposed from several aspects including new experimental equipment, micro mechanism and numerical modelling study.