The biomass continuous pyrolysis reaction device with a variable pitch spiral conveyor was developed. To be more specific, the special screw conveyer was designed and optimized. Cold experiments showed that pyrolysis volatiles could be smoother to the end by way of combining the variable pitch with pros and cons screw. For general biomass, the productivity of the device was about 30kg/h, and stay time was 5~10min, which can meet the needs of pyrolysis reaction stably and continuously. Experimental research for various agriculture and forestry biomass could be carried out.