Abstract: The present invention relates to a vertical pyrolysis reactor, including a reactor shell, a feeding device, a biomass gas outlet on the top of the reactor, an ash discharging device on the bottom of the reactor, and a grate inside the reactor. The feeding device is located on the bottom of the reactor, and an outlet of the feeding device is located in a central region of the bottom in the reactor for uniform material distribution. A slag breaking device is mounted in the pyrolysis reactor, forming an organic combination with the rotating grate. The output is adjustable through the operating speed of the grate. Precise control of a pyrolysis reaction is realized by controlling the feeding speed, discharging speed, material bed thickness, inlet air volume, inlet air distribution, reaction temperature, etc. Biomass having a size up to around 10 cm can be processed effectively and continuously due to the position design of the feeding device in conjunction with the use of the slag breaking device.