Semi-aqueous cleaning agent is a composite cleaning product composed of water, small amounts of low-VOC organic solvents, and surfactants. It not only retains the environmental friendliness and safety of water-based cleaning agents but also enhances the decontamination ability against insoluble contaminants such as heavy oil stains and adhesive residues by virtue of organic solvents. Compatible with most substrates, it is widely used in industrial heavy-duty contamination cleaning and precision component processing, perfectly filling the application gap between water-based and solvent-based cleaning agents.