The invention relates to the field of oral cavity cleaning and nursing materials, and discloses solid mouth wash which is prepared from the following raw materials in parts by mass: 40 to 90 parts of water, 3 to 35 parts of humectant, 0.1 to 0.8 part of surfactant, 0.01 to 2 parts of bacteriostatic agent, 0.01 to 2 parts of preservative, 0.01 to 2 parts of sweetening agent, 0.01 to 0.15 part of fluoride, 0.2 to 10 parts of excipient, 0.05 to 2 parts of essence and 0.01 to 2 parts of flavoring agent. The preparation method of the mouthwash comprises the following steps: S1, heating and uniformly stirring the pure water, the humectant, the surfactant, the bacteriostatic agent, the preservative, the sweetening agent, the fluoride and the excipient to obtain a system I; S2, after the system I is cooled, adding essence and menthol, continuing to stir uniformly, and standing to obtain the solid mouthwash. The mouthwash is not prone to leakage when squeezed, the problem that the carrying amount of liquid on an airplane is limited is solved, and carrying is very convenient.