To understand the evolution of coke in the catalytic conversion of biomass-derivates, in-situ diffuse reflectance Fourier transform infrared spectroscopy experiments and ex-situ extraction method were combined to identify the coke species. Considering the ring-shape and unsaturation of furan as an important intermediate from biomass pyrolysis, other simplified biomass-derivates like tetrahydrofuran, butanol, ethylene glycol and methanol was also studied to investigate the effect of its chemical structure on coke formation. The ex-situ study showed that the performance in the induction period and deactivation stage was closely related to the functional group of biomass-derivates. Coke extraction of furan and tetrahydrofuran were of similar composition, which was of doubt. Combined results with in-situ diffuse reflectance Fourier transform infrared spectroscopy revealed that polymethyl benzaldehyde was the main composition of active coke in the catalytic conversion of furan, and then intermediate of benzofuran was detected, and finally alkyl naphthalene and polyaromatic hydrocarbons were formed by polymerization and hydrogen transfer. This study will provide guidelines to enhance hydrocarbon production from the viewpoint of active coke like pre-feeding of polymethyl benzaldehyde.