The invention provides a mold roller gap stepless automatic regulation device of a vertical annular mold straw briquetting machine. The mold roller gap stepless automatic regulation device comprises an upper press plate, a grinding disc, an eccentric shaft A, an eccentric shaft B, a vertical main shaft, a PLC (programmable logic controller), an intermediate relay, an electromagnetic valve, a miniature hydraulic pump, an oil tank, a branch oil pipe A, a branch oil pipe B, a push rod and a tray. Strain force sensors sense strain of the eccentric shaft A and the eccentric shaft B in real time and transmit information to the PLC, the PLC controls the electromagnetic valve and the intermediate relay to work, further, the extension and retraction of the push rod are controlled through oil pressure, a mold roller gap is automatically regulated in a stepless way, the effective regulation on the mold roller gap is realized, the stability of forming extrusion force among grinding rollers is ensured, in addition, the briquette forming quality and the briquette forming uniformity are improved, meanwhile, the excessive abrasion among mold rollers is also reduced, the service life of each mold roller is prolonged, and the energy consumption during the production is also reduced.