Abstract: To clarify the influence mechanisms of physicochemical properties of biomass pellets on pneumatic conveying and fluidization characteristics, and to reveal the evolution of their performance before and after pyrolysis, thereby providing theoretical support for the optimization of gasification process parameters. Three types of woody biomass pellets—pine (I), construction wood (II), and mixed wood (III)—were selected as the research subjects. Thermogravimetric-differential thermogravimetric analysis (TG-DTG) was employed to determine the pyrolysis temperature intervals at different heating rates. The physicochemical properties before and after pyrolysis were characterized using scanning electron microscopy (SEM), X-ray fluorescence spectrometry (XRF), a density meter, and ImageJ software. Conveying and fluidization behaviors were analyzed through experiments combined with the Reh Diagram (Reh). The pyrolysis interval for the three types of biomass was 150–700℃. After pyrolysis, the particle size decreased, density reduced to 1/2–1/3 of the original value, and compressive resistance significantly declined. The proportion of carbon element increased, and pores and cracks became more numerous, with char particles exhibiting staged stress release. Among the char particles, those from construction wood showed the best compressive resistance, while construction wood also had the highest H/C ratio and energy density. Before pyrolysis, the conveying air velocity increased with density; at air velocities of 12–18 m/s, the feed rate increased linearly, while the growth rate slowed above 18 m/s. The minimum entrainment velocities of the three types of char particles ranged from 1.4 to 1.8 m/s, showing a positive correlation with particle size and density. This study clarifies the quantitative relationships between the physicochemical properties of biomass pellets before and after pyrolysis and their conveying and fluidization performance, providing an important theoretical basis for optimizing biomass gasification process parameters.