Oxidative torrefaction is a noticeable technique for industrial-scale biochar production for fuel, soil amendment, and carbon storage due to its low technological and economic requirement. In this study, two microalgal biomass (Nannochloropsis Oceanica and Chlorella sp.) under the influences of different torrefaction parameters (i.e., temperature, duration, and carrier gas) are analyzed. To evaluate the variations of the properties of biochar from non-oxidative and oxidative torrefaction, specific surface area, contact angle, particle size distribution, and scanning electron microscope are measured and characterized. The results indicate that oxidative torrefaction shortens the torrefaction duration and possess higher energy efficiency, decarbonization, dehydrogenation, and deoxygenation when compared to non-oxidative torrefaction. Biochar produced from oxidative torrefaction has bigger surface area, better hydrophobicity, and palletization behavior, and thus obtained better fuel properties for combustion and industrial application. Nevertheless, the transportation property of biochar produced through oxidative torrefaction is not as good as that via non-oxidative torrefaction ones. For the two types of torrefaction, particle agglomeration, fragmentation, and pore-forming behaviors of the biochar are apparently observed.