Hydrothermal treatment (HTT) of biomass is a technique which using hot, pressurized water to convert biomass for yielding a solid, coallike product. Therefore, the treatment and utilization of HTT liquid products has a key effect on its commercial application. This current research work mainly focuses on the effects of products on characteristic from HTT which using recycled process water for multiple process cycles. The hydrothermal experiments were carried out in an autoclave using wheat-straw as raw materials at temperature 220℃ for residence time 120min with a 30∶1 water and biomass mass ratio. The micro-structure, chemical composition and thermal stability of solid products were characterized by using X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Thermogravimetric analyzer (TGA) with differential scanning calorimetry (DSC). The results show that with successive recycling, the mass yield and sequestering carbon rate in the solid gradually increased. Compared with the initial HTT, mass yield and sequestering carbon rate after six recycles rose to 78.7% and 92.4%. Upon increasing recycling, the level of structural order in the solid increased, which suggested that the solid tended to further aromatize/graphitize. At the same time, the functional group and aliphatic structure decreased. The TGA analysis results indicated that the thermal stability of solid also increased as the number of cycles increased. Water recirculation during hydrothermal treatment of wheat straw could increase the HTT solid yields and improve their physical and chemical characteristics. 