Hydrothermal carbonization (HTC) was employed to produce hydrochar from bamboo (Phyllostachys heterocycla cv. pubescens) shoot shell (BS) at severity (combined temperature and time) of 4.83-7.69. The pyrolysis and thermodynamics properties of the hydrochars were fully investigated. The results showed that the hydrochar properties (solid yield, C content, H/C and O/C atomic ratios, pyrolysis yield, pyrolysis index, formation of enthalpy, exergy, LHV, and HHV) of BS were highly dependent on severity and could be expressed by dose-response functions. The rapid variations of the hydrochar properties appeared at severity of 5.93-6.59. The pyrolysis temperature interval for the maximum weight loss shifted from 300 to 400 degrees C at hydrothermal severity less than 6.59 to 400-500 degrees C at hydrothermal severity greater than 6.59. The hydrochar thermal stability increased greatly with the severity increasing. And the thermodynamic properties of hydrochar approached those of lignin model compounds as the hydrothermal severity was greater than 6.59. (C) 2017 Elsevier Ltd. All rights reserved.