In this work, H2 production from supercritical water gasification (SCWG) of chicken manure in a high heating rate batch reactor under different temperatures (500–620 °C) and residence times (1–12 min) was studied, and a quantitative kinetic model was employed to study the reaction mechanism and optimize the H2 production. The H2 yield, hydrogen gasification efficiency (HE) and carbon gasification efficiency (CE) were promoted with the growth of temperature and residence time. The maximum H2 yield, HE and CE reached 22.47 mol/kg, 174.53% and 81.34% at 620 °C and 12 min, respectively. The results of kinetic model indicated that higher temperature accelerated the reaction rate and more intermediates were converted into gas products. H2 was mainly produced by the steam reforming reaction and the generation rate of each gas decreased to be negligible after 10 min. High temperature from nearly 580 °C was preferred to accelerate water gas shift reaction (WGSR) to promote H2 production in SCWG of chicken manure. Hydrolysis reaction of chicken manure has a very important effect on H2 production.