In order to understand the physicochemical properties of buckwheat straw biochar，the effect of differenttemperatures and heating rates on the pyrolysis characteristics of buckwheat straw wasinvestigated，and the physicochemicalcharacteristics of buckwheat straw biochar were revealed by differential scanningcalorimetry，specific surface area and pore size and Fourier infrared spectroscopy. The results showed that the differential heat curves of buckwheat straw at differentheating rates had a similar changecurve，the pyrolysis reaction shifted to the right with the increase in the heatingrate；Theyield of biochar was negatively correlated with pyrolysistemperature；pH and conductivity graduallyincreased(9.16-12.27and 2.56-4.96mS/cm)；With the increase of pyrolysistemperature，the types of surface functional groups of buckwheatstraw biochar gradually was decreased，and the stretching vibration was increased with the increase of heating rate. Thespecific surface area and pore volume of biochar increased with the increase in pyrolysis temperature and then decreased，but there was no correlation with the rate ofheating，at lowertemperatures，with the increase in the rate ofheating，porestructure gradually transitioned from mesoporous to macroporous；The fractal dimension range of buckwheat straw biocharprepared at different pyrolysis temperatures was[2.3709，2.9368]. In summary，the buckwheat straw biochar prepared under the conditions of pyrolysis temperature of 700℃ and heating rate of 12.5℃/min had the best comprehensive propertiesin terms of its stablestructure，maximum specific surface area and high biochar yield.