Abstract: Biomass gasification was regarded as one of the promising technical routes for clean and high-value utilization of solid biomass resources. Severe particle fragmentation and unstable fluidization often occur in engineering practice, which easily cause pipeline blockage, uneven bed material distribution and low gasification performance. Such operational irregularities are closely bound up with the evolution of particle physicochemical properties during pyrolysis heating. Many previous investigations focused mainly on product distribution and reaction kinetics of biomass pyrolysis. Less attention has been paid to the mechanical and hydrodynamic behaviors of solid particles after thermal treatment. It is often required to quantitatively describe how pyrolysis-induced variation of density, particle size and compressive properties interferes with pneumatic transport and fluidization performance. Solid particles can be subjected to sequential processes in circulating fluidized-bed gasification, including pneumatic feeding, heating-induced pyrolysis, and fluidized gas-solid reaction. Physical and chemical properties of biomass particles can dominate the fluidization behavior during biomass fluidized conveying and gasification. Their changes before and after pyrolysis directly affect the efficiency of pneumatic conveying fluidization. In this study, typical raw wood materials were selected from softwood, construction waste wood and mixed hardwood. Among them, three types of wood-based biomass particles were taken as the research objects, including pine (I), pallet wood/roof beam wood (II), and jujube wood/willow wood / miscellaneous wood (III). The pyrolysis temperature range was determined by thermogravimetric-differential thermogravimetric analysis (TG-DTG). The particle density, particle size, and compressive strength before and after pyrolysis were characterized using scanning electron microscopy (SEM), X-ray fluorescence spectrometer (XRF), density meter, and pressure gauge. The correlation between physicochemical properties and conveying/fluidization was constructed to combine with elemental composition and microscopic morphology. A series of experiments was conducted to verify the wind speed for pneumatic conveying before pyrolysis. The fluidization of semi-char particles was predicted in the circulating fluidized bed after pyrolysis using the Reh diagram. The results show that the pyrolysis of the biomass occurred in the range of 150-700 ℃. The particle size and compressive strength decreased significantly after pyrolysis, while the density reduced to 1/2-1/3 of the original. The H/C ratio of semi-char particles was ranked in descending order: II > III > I. The semi-char of type II biomass had the fewest cracks and the highest compressive strength. Prior to pneumatic conveying for pyrolysis, the higher the particle size and density were, the higher the required wind speed was. Semi-char was prone to fragmentation after pyrolysis due to the reduction in compressive strength, leading to a decrease in particle size and density. A low gas velocity of 1.5 m/s achieved fluidization in the circulating fluidized bed after the Reh diagram fluidization prediction. Mechanical properties, elemental features, and microstructure were obtained over the pyrolysis stage. Reh diagram was introduced to assess the fluidization performance of pyrolyzed semi-char, bridging material physicochemical indices and actual hydrodynamic parameters. There was a close relationship between the physicochemical properties of biomass particles before and after pyrolysis and their conveying and fluidization behavior. The findings can provide a theoretical basis to optimize the parameters of gasification. It can also offer practical reference for parameter setting of feeding-pyrolysis-gasification systems in industrial biomass fluidized-bed facilities.