Abstract-TOUGHVISUAL is a full Windows-based graphical user interface for the TOUGHREACT program. TOUGHREACT is a general multiphase multicomponent reactive transport simulator, developed by introducing geochemistry into the multiphase fluid and heat flow code TOUGH2. TOUGHREACT has been widely used internationally for CO2 geological sequestration, nuclear waste disposal, groundwater remediation and geothermal energy development. The complexity of the input files (such as "flow.inp", "solute.inp" and "chemical.inp") required by original TOURHREACT, makes manual construction of these input files tedious and error-prone, especially dealing with complex geological structures and irregular study region. For this reason, we attempted to develop a new user-friendly interface. Here, we present a description and application examples of the improved pre-and post-processing graphical user interface TOUGHVISUAL. This interface can interactively create geometrical models, define related properties for multiphase flow and reactive transport, run the model, and view the simulation result. The interface offers a conceptual model approach and local grid refinement. It can deal with complex geological condition and heterogeneous media, and can share file data with other software to build a field-scale model.