In this study, L-rhamnose monohydrate (LRM) was used as a model compound of seaweed polysaccharide to study its pyrolysis and catalytic pyrolysis mechanism. Initially, the weight loss curve of LRM was obtained by thermogravimetric analysis. The main weight loss temperature was found to be at 350-550 degrees C. Then, the pyrolysis mechanism of LRM was analyzed and verified by macroscopic experiments and molecular simulations. Experiments showed that the bio-oil yield was highest when the temperature reached around 500 degrees C, and the bio-oil contained large amount of furan substances. Finally, the effects of different proportions of catalysts (Mg-Ce/ZSM-5) on bio-oil products were studied, and the catalytic reaction mechanism was discussed. (C) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.