The present study concerned the production of glucose-based porous carbon materials by a one-step acid-catalyzed HTC. The samples were characterized by elemental analysis (EA), scanning electron microscope (SEM), Brunauer−Emmett−Teller (BET), Fourier transform infrared (FTIR) and point of zero charge (pzc). Experimental results showed that the addition of sulfuric acid (SA) with different dosages in the HTC system could improve the yield of products and reduce chemical oxygen demand (COD) of the process water. When the glucose and acid was at a mass ratio of 1:4 (glucose: SA = 1:4), the hydrochar obtained (H-G9) had a larger specific surface area (SBET = 296.71 m2/g) and higher abundance of functional groups on the surface than that of other samples, such as sulfur-containing functional groups and carboxylic groups, belonged to the mesoporous material with highly negatively surface charged. H-G9 exhibited the optimum adsorption for methylene blue (MB). H-G9 adsorbed MB with an initial concentration of 10 mg/L at pH 6 and 25 °C. The adsorption isotherm of MB on H-G9 demonstrated that Freundlich isotherm could be better applied. Regeneration efficiency of 88% was achieved by HTC process for saturated H-G9. This study prepared a porous carbon material by the simple one-step hydrothermal carbonization of glucose in the presence of SA. The maximum monolayer adsorption capacity as high as 332.46 mg/g for MB, which was well beyond that of commercial activated carbon (259.37 mg/g). This indicates that H-G9 has great potential for the removal of MB from wastewater.