The invention belongs to the technical field of biomass energy and particularly relates to a biomass liquid fuel mixing and stirring device. The stirring device comprises a stirring barrel with an opening in the top part and a sealing cover matched with the opening in the top part of the stirring barrel, wherein a through hole is formed in the top of the sealing cover; an output shaft of a motor passes through the through hole and is connected with a crank stirring rod in the stirring barrel; the sealing cover and the crank stirring rod are spaced from the inside of the stirring barrel through a leakage-proof leather sheath. The biomass liquid fuel mixing and stirring device is simple in structure and ingenious in design and is capable of comprehensively stirring and mixing different mixed fuels in a liquid fuel container; on the one hand, different liquid fuels are mixed, mutually dissolved and blended, so that the mixing efficiency of different fuels is improved; on the other hand, leakage and volatilization of the liquid fuels and the problems of waste, pollution and safety caused by the leakage and the volatilization of the liquid fuels are avoided; the efficient utilization of biomass resources is finally accelerated.