In order to explore the bonding mechanism of DRI in gas-based shaft furnaces and analyze the internal relationship between the bonding phenomenon and the production process，the direct reduction process of the shaft furnace is simulated by cold-consolidated pellets by high-temperature reduction test，and the morphology，composition and bond structure of the reduced pellets are observed and characterized by SEM and EDS. The results show that the TFe mass fraction of the inter-pellet binder is as high as 93. 56% ，and the TFe mass fraction of the clastic binder is low at 53. 88% due to gangue enrichment. The bonding between pellets is mainly caused by the aggregation and growth of iron after reduction，and the process can be divided into two stages：low-temperature solid-phase sintering below 800 ℃ and high- temperature reduction fusion at 800 ~ 900 ℃. The bonding morphology is affected by particle contact，diffusion and high- temperature fusion，among which the diffusion and recrystallization of iron atoms at high temperature stage are the key to bond strengthening. DRI bonding is unavoidable，but the degree of bonding can be reduced by controlling the strength of the raw material，reduction temperature，metallization rate，etc. The results can provide a theoretical basis for optimizing the production process of gas-based shaft furnaces and improving the quality of DRI products.