Paulownia wood was used as a raw material in the preparation of activated carbon by chemical activation with phosphoric acid. The conversion of wood into activated carbon consists of sample preparation, impregnation, carbonization, and finishing. Mass changes associated with the impregnation, filtration, carbonization, and washing processes were measured, and the yields of these processes were calculated and analyzed. The effects of final carbonization temperature (300-600 degrees C) and impregnation ratio (1-4) on the yields of chemical activation stages were investigated. Experimental results show that the final carbonization temperature and impregnation ratio have a significant effect on the yield of these stages.