The decomposition and calcination characteristics at high temperatures of calcium-enriched bio-oil (CEB) were investigated from 900 to 1100 degrees C in the study. The CEB were produced by reacting bio-oil with calcium hydroxide, which combined the functions of desulfurization and providing heat during the decomposition and calcination processes. The decomposition of CEB consisted of four steps, partly similar to the case of pure calcium acetate (CA). The rate of the final step, i.e., the calcination rate to derive CaO, was higher in the case of CEB than in the case of CA. The alkali metal migrated from bio-oil might accelerate the calcination rate of CEB-derived CaCO3 and sintering rate of CaO. The porosities of CEB-derived CaO particles were higher than that from CA, but the Brunauer-Emmett-Teller (BET) surface areas were lower. Dried CEB of pH 10.0 (CEB 10) were typical amorphous solids, which should be the optimum bifunctional material with a medium heating value. The decomposition of CEB 10 yielded porous CaO particles of moderate surface area and sintering rate for potential SO2 capture.