The desorption process of volatile organic compounds (VOC) from a polymer adsorbent in counter-current mul-tistage fluidized bed was studied. And a mathematical model considering the mass transfer dynamics was devel-oped, which was validated from experiment data. The gaseous ethyl acetate mass transfer was discussed, and the limiting step is the intraparticle mass transfer of the desorption process. The value of intraparticle mass transfer coefficient is between 1.85 × 10?6 and 1.38 × 10?5 m·s?1 under temperature of 100–160 ℃. Experiments under different operating conditions were carried out. The effects of operating conditions such as gas–solid flow ratio, gas inlet temperature and total stage number of multistage fluidized bed on outlet VOCs concentration and de-sorption efficiency were discussed. The maximum outlet VOCs concentration and corresponding desorption effi-ciency of the multistage fluidized bed desorber was calculated under different gas inlet temperatures and total stage numbers.