The hydrothermal treatment process is an effective thermal conversion of wet biomass to solid and liquid biofuels that avoids the drying of raw feedstock. The process takes place under heat and pressure in the presence of water which initiates a series of reactions including hydrolysis. This treatment might be used to hardly decomposing lignocellulosic biomass characterized by high moisture content. To boost its hydrolysis a steam explosion might be also employed. In the present study, the hydrolysis of wheat straw was carried out at 175°C for 0.5 and 2h treated by a quick wave of steam explosion in pilot hydrothermal unit. The process facilitated the lighter and deeper decomposition of the organic matter into smaller compounds eager to produce biogas. Hydrolysates were separated into liquid and solid residues. Solid residues were also tested in terms of their physical and chemical properties using the following instrumental techniques: fibre, ultimate and proximate analyses, and higher heating value. The TGA and FTIR analyses were employed to identify the degradation of lignocellulosic materials. These pretreatment facilitated biomethane potential of wheat straw confirmed by biomethane potential tests performed for pilot reactor. The results confirmed that the hydrothermal treatment effectively converted wet biomass into biofuels.