Abstract: Effects of steam-exploded stalk on high-temperature solid two-phase anaerobic fermentation was investigated to enhance anaerobic fermentation process．Optimal steam explosion conditions were determined experimentally．Based on these parameters, effects of stalk particle size and adding exogenous additives（Fe₃O₄）and biochar on acid and gas production during high-temperature solid two-phase anaerobic fermentation were further examined．Results showed that yield of volatile fatty acids（VFAs）from steam-exploded stalk with different particle sizes was consistently higher than that from untreated stalk．Analysis using Modified Gompertz model across three experimental treatments of 1 to 3 cm untreated stalk, steam-exploded stalk, and steam-exploded stalk with additives, showed significantly increased methane yield in latter two treatments compared to untreated stalk．Steam explosion treatment and reduced particle size improved high-temperature solid two-phase anaerobic fermentation performance of stalk．Additives further enhanced methane yield in anaerobic fermentation when applied after steam explosion pretreatment, effectively promoting anaerobic fermentation process of stalk．