Abstract: Biomass energy is a renewable energy. It is abundant in resources, and has net zero emission of CO2 and relatively low nitrogen and sulfur contents, and is widely found in the world. More attention has been paid to its utilization. Co-firing biomass with pulverized coal particles provides an effective manner to utilize biomass energy. Biomass particles are generally much irregular-shaped. They have large aspect ratios and exhibit obvious non-spherical characteristics. For biomass particles moving and burning in a combustor, the turbulent fluctuation of gas velocity has evident effects on the particle motion. But whether the gas turbulent fluctuation imposes influences on the reaction processes of non-spherical biomass particles needs to be studied. The effects of gas temperature fluctuation on the instantaneous char combustion of non-spherical biomass particles in a hot gas were explored in the present paper. Biomass particles with prolate spheroidal shapes were studied. The theoretical expressions for both mass transfer and heat transfer enhancement factors of prolate spheroidal particles were employed in algebraic forms. They are functions of particle aspect ratio. The Sherwood number or Nusselt number for the prolate spheroidal particles can be expressed as the product of the enhancement factor and the Sherwood number or Nusselt number for the spherical particles. Thistle and pine are 2 types of biomass fuel. Their instantaneous char reaction processes were calculated. The thistle particles have aspect ratios of 1.4, 4, and 7. The aspect ratios for the pine particle are 5 and 10. The gas flow has a time-averaged temperature of 1 000 and 1 100 K. The fluctuation amplitude of the gas temperature was chosen to be 0, 0.1 and 0.2. Both thistle and pin particles have the same initial diameter of the equal-volume sphere. Its magnitude is 200 ?m. The instantaneous variations of particle mass and char combustion rates with time were provided under different time-averaged gas temperature and particle aspect ratios. The results showed that the gas temperature fluctuation had evident influences on the instantaneous char combustion processes of biomass particles with different aspect ratios. It leaded to faster mass loss of the particles and shortened time for the char combustion. The increase in the fluctuation amplitude of the gas temperature would further enhance the instantaneous mass loss of the particles with different aspect ratios. The instantaneous char reaction processes of both thistle and pine particles were affected by the gas temperature fluctuation. As a result of gas temperature fluctuation, the particles lost their mass and the char burns out at faster rates. The instantaneous char combustion rates of the biomass particles with different aspect ratios exhibited smooth variations with time when the gas temperature fluctuation was not considered. While fluctuating variations with time were found for the instantaneous char combustion rates of the biomass particles obtained with the gas temperature fluctuation. The present study reveals the effects of turbulent fluctuation of gas temperature on the instantaneous char combustion processes of non-spherical biomass particles. The influences will not change when the particle aspect ratio experiences variations.