The invention discloses a biomass micro-positive-pressure pneumatic transmission system which comprises a feeding system, a fan, a conveying pipeline system, a discharging system, a tail gas treatment system and an automatic control system, wherein the feeding system comprises a quantitative feeding device, a collecting device, a positive-pressure air sealing device, an accelerator, an air guide pipe and a return air treatment pipeline; the conveying pipeline system comprises a straight pipeline, a connecting flange and a plurality of quick-operating doors distributed on the pipeline as well as a transparent observation window. The biomass micro-positive-pressure pneumatic transmission system has the advantages that smooth feeding with higher concentration ratio can be achieved, the power consumption is low, the service life of the air sealing device is prolonged, the applicability and the pipeline durability of the conveying system are improved, the convenience is provided for pipeline smoothening and repairing, the environmental pollution can be avoided, and the automation level is high.