The effect of Na2CO3, Fe and Na2CO3+ Fe during hydrothermal liquefaction ( HTL) of wheat stalk with different temperature and reaction time was investigated in this study. The results indicated that Na2CO3+ Fe can promote the cracking of wheat stalk compared with Na2CO3 or Fe. Meanwhile, higher temperature favored the decomposition of wheat stalk and formation of heavy bio-oil. The highest heavy bio-oil yield was 24.25 wt% and the maximum liquefaction conversion rate was 89.45 wt% in system of Na2CO3+ Fe at 270 degrees C. The analysis results indicated that longer reaction time could promote liquefaction conversion especially for heavy bio-oil with Na2CO3+ Fe during the process of HTL. GC-MS, UPLC-MS and FT-IR analysis indicated that the major organic compounds in heavy bio-oil were aromatic compounds, alcohols, ketones, alkanes, and aldehydes, among of them aromatic compounds were the most prevalent.